Keeping His Promise

Context: Genesis 20:1–21:34

Memory Verse: Genesis 21:1

Main Idea: God keeps His promises and can be trusted.

FIRST THOUGHTS

        If a child is asked to jump from a high place into the arms of an adult, some questions may arise. “Can the person telling me to jump be trusted? Can I trust the fireman to catch me? Can I trust my father to keep his word and not let me fall? Has this person been trustworthy in past experiences?” A good deal of trust is involved in jumping from a tree branch or some other high place. The act raises legitimate questions about the strength, ability, and trustworthiness of the other person involved. A wary child understandably may pause before leaping in such a situation. The trustworthiness of the adult is a crucial part of the decision.

        What emotions are experienced on both ends of such a leap, for the one jumping and the one catching? How important is the trust factor in such a situation?

        Genesis 21 tells the story of the fulfillment of God’s promise to Abraham and Sarah. God asked them to trust Him with their future just like a child is asked to trust his father and jump into his arms. They followed God by faith into a new land and now, years after the original promise of offspring, they saw God’s promise fulfilled. Their leap of faith into the future God had for them was met by the faithfulness of the Lord in providing a son and keeping His word. God asks us to trust Him with our lives and our future. He is strong enough to take care of us. His Word is dependable and trustworthy. He asks us to trust Him fully and completely with every part of our lives.

I.                 UNDERSTAND THE CONTEXT (Genesis 20:1–21:34)

        After the destruction of Sodom and Gomorrah, Abraham migrated southwest. Moving into a new territory revived old fears, and Abraham replicated his previous behavior by passing off his wife as his sister (Gen. 12:10-20). Consequently, Abimelech, the king of Gerar, acquired her for his harem (20:1-2).

        Abimelech’s acquisition of Sarah threatened the Lord’s promise to her. Less than three months had passed since God promised that she would give birth to son (18:10,13-15). If she conceived while living in Abimelech’s harem, the child would not be Abraham’s promised heir. If she already was pregnant, the infant still would be reared as the child of Abimelech and God’s promise to Abraham might be thwarted.

        God’s mercy kept Sarah from being touched. He protected the king of Gerar from divine wrath while safeguarding Sarah’s purity and the legitimacy of her child. Likewise, God’s intervention demonstrated that His promise was not contingent on Abraham’s faultlessness. God’s grace facilitates the realization of His promises even though individuals do not deserve their fulfillment. God’s warning established that He would take whatever measures necessary to keep His promise to Abraham and Sarah. Abimelech’s possession of Sarah compromised that promise. Therefore if the king did not return her to Abraham, God would kill Abimelech and annihilate his entire household. God’s instructions to him also included the first reference to prayer in the Bible (20:7).

        Abraham sought to justify his actions on the basis of the local population’s different religious beliefs and Sarah’s family tree. The inhabitants of Gerar did not worship the Lord. Furthermore, Sarah, in reality, was Abraham’s half-sister. However, neither argument justified Abraham’s conduct. Relying on such subterfuge belies a lack of faith in God. A declaration that is partially true is still a false statement. Abraham acquired additional wealth as a result of this episode. This did not vindicate bad behavior. Rather, it confirmed God’s original promise that He would bless and protect Abraham. Later, Abimelech and Abraham ratified a formal treaty between themselves (21:27-34)

        God is faithful. Within the year specified, Sarah became the mother of Abraham’s son. The couple named him Isaac in obedience to the Lord’s instructions (see 17:19). However, the boy’s weaning celebration rekindled Sarah’s rivalry with Hagar and forced Abraham to banish Hagar and his eldest son, Ishmael. God did not abandon the displaced mother and child. Instead, God reaffirmed His promise that Ishmael would rise to greatness (21:18-20).

II.              EXPLORE THE TEXT

1.      GOD’S PROMISE REALIZED (Gen. 21:1-2)

          ¹ The Lord visited Sarah as he had said, and the Lord did to Sarah as he had promised. ² And Sarah conceived and bore Abraham a son in his old age at the time of which God had spoken to him.

        Just as God had promised, Sarah and Abraham became the parents of a son.

VERSE 1

        The words the Lord visited and the Lord did point to God’s intervention in Sarah’s life. Note that in both clauses Lord is printed in all capital letters. This format indicates that the Hebrew text contains the covenant name Yahweh. There can be no doubt as to who was responsible for what occurred in Sarah’s life. The conception of Isaac was the foretold act of God.

        The words concerning Sarah point to God’s concern and activity in the lives of all people. The world in which Sarah lived was a male-dominated culture. Women were virtually property of men. Yet here the Bible says the Lord kept His promise to Sarah. That promise was made to both her and to her husband Abraham (17:19; 18:10,14). The promise was made to Abraham first when he had been chosen by God for a special role in human history (12:1-3). One would expect the text to say, “the Lord did for Abraham what He had promised.” But instead it addresses His promise to Sarah. Every individual is important to God, and His promises to them matter to Him.

        As he had said and as he had promised weld the events in this passage to God’s statements in the past. The repetition emphasizes the certainty of God’s words. Specifically, this verse relates to God’s promise that Sarah would have a son in about a year’s time (18:10,14). On that occasion, the Lord repeated His promise twice to indicate the inevitability of its fulfillment. The dual parallel wording here stresses that God is faithful in accomplishing everything just as He said.

VERSE 2

        In simple, straightforward statements, Scripture reveals the specifics of the divine fulfillment. Sarah conceived a child through the natural procreative process. The child was a boy. The father was Abraham. He was an elderly man when his son was born. And the birth transpired exactly as the Lord stipulated it would.

        The realization of the Lord’s promise that Sarah would give birth to a son within a year’s time validated God’s other promises that were yet to be fulfilled. God previously said that Abraham’s descendants would become as numerous as the stars in the sky (15:5). But even this was only descriptive of an earlier promise to make Abraham into a great nation (12:2). However, the most significant descendant to come out of God’s promise was the One who would bless “all the families of the earth,” the Messiah (12:3b).

        At the time indicated that the time of the birth was fixed by God and occurred on schedule. Likewise, the birth of the Messiah would occur at the time established by God (see Gal. 4:4-5). God has an appointed a time for all His promises to be realized (see Acts 1:7).

        In what ways could it have been advantageous for Abraham and Sarah that God waited 25 years to fulfill His promise to them? In what ways can God’s delay in answering our prayers be a blessing?

2.      GOD’S PROMISE REMEMBERED (Gen. 21:3-7)

          ³ Abraham called the name of his son who was born to him, whom Sarah bore him, Isaac. ⁴ And Abraham circumcised his son Isaac when he was eight days old, as God had commanded him. ⁵ Abraham was a hundred years old when his son Isaac was born to him. ⁶ And Sarah said, “God has made laughter for me; everyone who hears will laugh over me.” ⁷ And she said, “Who would have said to Abraham that Sarah would nurse children? Yet I have borne him a son in his old age.”

        Isaac’s circumcision and name would be a constant reminder of God’s covenant and faithfulness.

VERSE 3

        Names were important in biblical times. The child’s mother customarily named the newborn. Abraham took the lead here because God had specified the boy’s name (see 17:19). The name supposedly expressed the essence of the individual who bore it and was thought to reveal the child’s character and destiny. Whenever the name was given by God, parental hope became divine reality. God instructed Joseph to name Mary’s baby “Jesus”—which means “Yahweh is salvation”—because Jesus would save people from their sins (Matt. 1:21).

        In obedience to the Lord’s instruction, Abraham named Sarah’s newborn son Isaac. The name Isaac means “laughter.” Both Abraham and Sarah laughed the first time they heard God’s announcement (17:17; 18:12). The thought of having children at their advanced age struck both as comical. The notion was so absurd and amusing they could not control their reaction. Both questioned the veracity of God’s announcement. A year later an incredible prediction had become a living infant. His birth transformed their skepticism into joyful laughter. The name constantly reminded them—and us—of the dependability of God’s promises. Every time they called out Isaac’s name, God’s rhetorical question, “Is anything too hard for the Lord?” (18:14) surely echoed in their memory.

        The Hebrew construction of this verse intensifies the identity of the birth mother. The redundancy of born to him and bore him reinforces Sarah’s significance in Isaac’s birth. She ensures he is the promised successor to the covenant God made with Abraham. In addition, this emphasis points to the importance both parents have in rearing children.

VERSES 4-5

        The obedience implicit in the naming of the newborn is stated explicitly concerning the child’s circumcision. Abraham’s covenant relationship with the Lord was established through his faith (see 15:6). Integral to faith is obedience. Abraham’s journey began when he obeyed God by departing Haran for an undetermined destination (12:1). Abraham was circumcised in obedience to God just a year before Isaac’s birth (17:24). At that time, God specified that subsequent generations likewise must be circumcised as a sign of their covenant relationship (17:12). God commanded the procedure be done eight days after birth. So eight days after Isaac’s birth, his father circumcised him.

        A 90-year-old barren woman cannot give birth to a child fathered by a 100-year-old man. It is not biologically possible. But even when God’s promises seem impossible, He fulfills them. In the case of Isaac’s birth, God had promised Abraham an heir whose mother would be Sarah (15:4-5; 18:10-14). Moreover, a hundred years here contrasts with “ninety-nine” in Genesis 17:1 to corroborate that the birth occurred within the one-year time frame specified in Genesis 18:10-14. Every detail spoken by the Lord is certain.

        One application of this certainty shapes the absolute dependability of the Bible. Scripture is not human opinion. It presents God’s word to humanity and is the product of divine inspiration (2 Tim. 3:16-17; 2 Pet. 1:20-21). Jesus taught that even the smallest letter or slightest mark is dependable (Matt. 5:17-18). Therefore, while difficulties in translation may exist, we can trust the English Bible we are studying today. As we read its words, we can hear God speaking to us and know that what He says is true.

        How were the actions of Abraham a demonstration of faith in God? What relationship does our faith in God have to our obedience of God?

VERSES 6-7

        Whereas the previous verses narrate the birth of Isaac, verses 6-7 set forth Sarah’s perspective after the birth. Foremost, incredible joy had replaced her cynical mirth. Her use of the verb laugh entailed a gleeful wordplay on the name Isaac. Her joy was contagious. Everyone who knew Sarah would rejoice with her.

In the biblical narrative, Sarah, then known as Sarai, first appears as Abraham’s wife while his family still lived in Ur. Genesis 11:30 notes “Sarai was barren; she had no child.” Even though Abraham and Sarah worshiped the Lord, children remained an unsatisfied yearning within Sarah. Her lack of children fostered a lifelong stigma (see 16:2). Deep inside, she harbored a sense of great personal failure. No doubt her individual despair was compounded by her husband’s yearning for a son of his own. Although an acceptable alternative in her culture, recruiting her handmaid as a surrogate mother only worsened her sense of inadequacy and generated conflict within her household (see 16:5-6).

        Sarah’s previous despondency and jealousy shines through her rhetorical question, “Who would have said to Abraham that Sarah would nurse children?” Nevertheless, her current joy overwhelmed her so that she could not refrain from answering, “Yet I have borne him a son in his old age.” Not only did motherhood satisfy her inner aspiration for children, it gratified her desire to please her husband. She had given to him that which he wanted more than anything else in life.

        What are inadequate excuses people use to explain why they cannot serve the Lord right now? How does Sarah’s life counter those excuses?

3.      GOD’S PROMISE REJOICED (Gen. 21:8)

          ⁸ And the child grew and was weaned. And Abraham made a great feast on the day that Isaac was weaned.

At the appropriate time, Abraham celebrated the birth of Isaac. This event served as a rite of passage for Isaac as well as a day of celebration for his family.

VERSE 8

        Egyptians nursed their children for three years. In some other ancient cultures children were nursed as late as age five. Even today weaning in the Middle East often does not occur until three or older. Although the Bible does not indicate his age, Isaac likely was weaned around two or three. 

        In that region of the world, celebrations sometimes were held to mark the weaning of a child. Just how common these celebrations were is not certain. Abraham’s great feast may simply have conformed to the custom of the region, or it may have been an extremely proud parent expressing overwhelming joy over a child’s accomplishment. In this case, the father had much to celebrate. Infant mortality was high in the ancient world, so Isaac had survived a critical phase of his life. Furthermore, his mother also had survived his birth. Death was not an uncommon consequence for women during childbirth. Older women experienced an even higher risk of fatal complications. Isaac’s daughter-in-law would die giving birth to her second child, and she was much younger than Sarah (35:16-20). Abraham had been despondent because he had no biological heir (see Gen. 15:2). Now he and his wife enjoyed the blessing of seeing their son growing physically and intellectually.

        This feast also functioned as a rite of passage for Isaac. It commemorated a positive step in his independence. Nursing forms a special bond between mother and child. Psychologically, the event assisted the child in making this life transition. Previously the child associated nursing with satiating hunger. Hereafter, he would replace his mother’s milk with grains, dairy products, fruits, vegetables, and meat as the staple foods of his diet. The taste and consistency of these foods differs greatly from a mother’s milk. For a very young child, dependence solely on them could be traumatic. The festivity encouraged him to make the transition efficaciously.

The celebration also signaled that Isaac had moved closer to receiving his inheritance as the heir of God’s covenant (26:2-4). God’s initial promises to Abraham were coming closer to realization (12:1-3). More importantly, God’s plan for the redemption of humanity was advancing towards its ultimate fulfillment in Jesus Christ.

        Adam and Eve’s disobedience in Eden unleashed a flood of repercussions for humanity. Their deed ended their unhindered relationship with God and sealed the fate of their descendants. Henceforth, sin would characterize everyone’s behavior. All human lives would terminate in death. But God promised that humanity ultimately would overcome sin and Satan (3:15). This victory was realized in Christ’s death and resurrection (1 Cor. 15:3-11,50-57) and is appropriated through faith in Him (Eph. 2:1-7).

        What are some ways that you celebrate the fulfillment of God’s promises? What promises do you anticipate God fulfilling in the future?

KEY DOCTRINE

God

To God, we owe the highest love, reverence, and obedience.

BIBLE SKILL

Investigate the context of a passage.

        Many words and phrases in Genesis 21:1-8 point back to previous events or statements from Genesis 17 and 18. Scan these two chapters, looking for phrases that appear in Genesis 21:1-8. Look at how all of these pieces fit within the overall story of Abraham’s life and God’s covenant with his descendants. What are the similar themes? How do these themes define Abraham?