Bible Studies on the Life of Abraham Lesson 10: As for You . . . Genesis 17:15–27; 18:1–15

The promises that God gave to Abram were for future generations. The promises God gives, however, are not only for some eventual fulfillment; they are for the present as well. After changing Abram’s name to Abraham, God addressed the rest of the patriarch’s family.

As for Sarai

The member of the covenant family God mentioned first was Abraham’s wife. Having changed Abram’s name to mean “father of a multitude,” the sovereign God changed Sarai’s name to Sarah. Both names mean “princess.” The change, however, was significant. “Sarai” pointed to a past noble descent; “Sarah” pointed ahead to the promises that God was yet to fulfill. God promised Abraham that his wife would be the mother of nations, kings, and peoples. By doing so, God affirmed His continuing presence and purpose in her life.

There are different ways to interpret Abraham’s laughter toward the promise given to Sarah. Some interpret Abraham’s laughter as an indication of his unbelief; others as a man whose faith is still weak. He could not see how he, at one hundred years old, and Sarah, at ninety years old, could possibly have a child together. Abraham then pointed to Ishmael, telling God that he was content that the terms of the promise God had given to him were fulfilled in his one son born to him through Sarah’s handmaiden.

Others teach that Abraham’s laughter was an expression of thanksgiving and gladness. His questions, then, are asked not from doubt but from surprise and wonder. With keen understanding that the child born to Sarah would be the child of the promise, Abraham then asked God to provide a blessing for his son Ishmael, as well.

Sarah’s laughter (Genesis 18:12) on the other hand, was different from that of Abraham. Her laughter came more out of unbelief that God could still use her to fulfill His promise. After all, she was ninety years old, well beyond the childbearing years. It almost seemed more a scoff than a laugh. To scoff before God is sin. Sarah had been looking at circumstances rather than God. For a dozen years she believed that God had already fulfilled the promise through Ishmael. When confronted with her sin, she denied her laughter, leading to more sin.



Yet God was merciful. He responded with the words, “Is anything too hard for the Lord?” (Genesis 18:14). Sarah was promised that within the year she would have a son. And so it came to pass. Her scoffing laughter was turned into true laughter (Genesis 21:6, 7) and she named her son Isaac, which means “laughter.”

As for Ishmael

At Abraham’s request, God also informed the patriarch as to the blessings that Ishmael would receive. As Abraham’s son, God would bless Ishmael, making him the father of twelve rulers. His descendants would become a great nation. Conspicuously missing from the blessing that God gave concerning this child of the patriarch were any covenant or redemptive promises. All that was promised to Ishmael were worldly and temporal blessings.

God made abundantly clear to Abraham that the covenantal blessings would be carried on through the son born to him by Sarah. Isaac was to be the channel of redemption and, in the fullness of time, the promised Messiah would come through him. Every time they called their son to the dinner table, they would remember the doubt they had once had and the faithfulness of God to His promises.

As for Abraham

On that very day every male in Abraham’s household was circumcised as the Lord had commanded. His immediate obedience illustrates not only his awe for the majesty of God but also his desire to actively walk in God’s will. Abraham’s faith was not something that came out only when God Almighty revealed Himself to Abraham. It was not only in worship as he lay face down before the presence of God; Abraham’s faith penetrated every area of his life, even to the most personal area of his life.

Many Christians today view their Christian walk as though they only need to follow Christ on the Lord’s Day—and then only for a few hours. They give an hour of worship to God in His house and then go their merry way. The rest of the day and the rest of the week is theirs to do as they please. As long as they go to church, follow the Ten Commandments, and stay away from certain worldly things, they are living in obedience to God. True obedience, however, is to love the Lord with heart, mind, and soul. To love someone is more than refraining from harming that person; it is positively promoting that person’s good. It is more than not stealing from him; it is giving to the one you love all that is yours. To love God is more than denying oneself a life of sin; it is actively pursuing a life that brings glory to God. Reading pornography, for example, is not only rejected; it is replaced by reading the Bible. Spending time in prayer is considered of greater value than spending time on Facebook. It is alarming how many hours we can fritter away on worldly activities and how little time we spend nurturing ourselves spiritually in devotion to God. Loving God is actively seeking His will and doing it.

As for Circumcision

The condition of the everlasting covenant placed upon Abraham was that he was to circumcise every male in his household. This he did, as would every future generation of those within the Old Testament covenant. The mark of the covenant certainly did not mean that all those who received the mark were automatically saved. Ishmael was circumcised on the same day as Abraham, but he showed no evidence of a heart renewed by the grace of God. Abraham’s grandchildren, Esau and Jacob, both received the mark of the covenant, yet Malachi makes clear that God hated the one and loved the other. Although these two children of the covenant bore the signs of that covenant, they were not ultimately part of God’s covenant people. They rejected the promises of salvation that God had given to them and were cut off from the people like a worthless piece of foreskin.

Throughout the Old Testament, it was made clear that the followers of the sovereign God were to have their hearts circumcised—that they are to be cut off from the world, a separate nation devoted to God. In the New Testament, Paul made clear that it was not the cutting away of the foreskin that brought one into the covenant. He wrote, “Circumcision is nothing and uncircumcision is nothing. Keeping God’s commands is what counts” (1 Corinthians 7:19). To the church in Galatia Paul wrote, “For in Christ Jesus neither circumcision nor uncircumcision has any value. The only thing that counts is faith expressing itself through love” (Galatians 5:6).

Paul based this upon the fact that Abraham received the covenant promises and was declared righteous prior to his circumcision (Romans 4). It was not Abraham’s circumcision that saved him. It was his faith in the promises of God—that one day God in His grace would provide the ultimate bloody sacrifice that would restore His people to Himself. The receiving or rejection of that promise—not the sign of the promise—determined one’s standing before God. All the sign did was to remind the Israelites that God would one day replace the bloody ritual with the blood of His own Son.

That still holds true today. Our faith must be the same as that of Abraham. We must trust that God in His grace has provided the ultimate bloody sacrifice that has restored His people to Himself. That sacrifice was made by God’s Son, Jesus Christ, on the cross of Calvary. The covenant-keeping God has replaced the bloody rite of circumcision with the sacrament of baptism (Colossians 2:11–13). It is not the water of baptism that saves. The water points us to the blood of Jesus Christ. At every baptism we should hear the words: “As surely as water washes away dirt, so sure can we be that the blood of Jesus Christ washes away our sins.”

That this sacrament is applied to all within the covenant should be obvious. Just like the future promise of a Messiah was given to all within the Old Testament, so also the promise fulfilled is for all within the New Testament—young and old alike. Just as Old Testament parents were to teach their children about the promise of the coming Messiah, New Testament parents are to teach their children of Messiah who has come.

Notice how those promises are from God. With believer’s baptism the promises are made by the individual promising that he will come to church, obey the Law, and serve God. On what can he base those promises? A totally depraved person can make all kinds of promises to serve God, but he is incapable of keeping any of them on his own. With covenantal, infant baptism, God makes the promises. As real as the promises are to the parents, so they are real and true to the children. The almighty God who walked between the carcasses of the animals declares to His people, “May it be done to Me as it was done to these animals if I do not keep My promises.” He promises that as real as is the water of baptism, so real is the blood of His Son shed for our sin; so real His faithfulness to those who keep covenant with Him.

How absolutely amazing that this God who said to Abraham, “I am God Almighty; walk before me and be blameless,” promises to make us blameless when we trust in the bloody sacrifice of His Son. Through His grace we are brought into the covenant, by His grace we remain in the covenant.

Rev. Wybren H. Oord is the co-pastor of the Trinity United Reformed Church in Lethbridge, Alberta, Canada, and the editor of The Outlook.

Points to Ponder and Discuss

1. How would you interpret Abraham’s laughter in v. 17? What does your interpretation indicate about Abraham’s faith?

2. Why would Abraham ask for a particular blessing upon Ishmael?

3. How does God have the last laugh by calling the promised son “Isaac,” which means “laughter”?

4. How is it significant that God promised to be a God not only to Abraham, but also to his seed?

5. How can Abraham’s obedience be a model for Christians today?

6. Why is circumcision no longer considered part of the eternal covenant?

7. Explain the difference between circumcision and baptism.

8. How was Abraham’s faith identical with ours?

9. What is the fundamental difference between infant baptism and believer’s baptism?