Genesis 17:20–21

“But I will establish my covenant with Isaac, whom Sarah shall bear to you at this time next year” (Gen. 17:21).

Like any good father who loves his son, Abraham earnestly sought blessings for Ishmael. His plea for God to fulfill His covenant promises in Hagar’s son (Gen. 17:18), as we saw yesterday, likely evidenced some doubt as to whether Sarah would ever be able to conceive as the Lord had said. But contributing to his request, almost certainly, was a genuine concern for his child.

God does not ignore Abraham’s request for divine favor upon Ishmael. Hagar has already heard that her son will be the father of a strong people (16:11–12), yet Abraham has not enjoyed hearing of this privilege directly. In today’s passage, God gives the patriarch a personal confirmation of His intent for Ishmael. Hagar’s son has not been forgotten, for he will father a great nation (17:20). Furthermore, though all of mankind has been charged to multiply and fill the earth, Ishmael will receive special aid to accomplish this task. God Himself will empower this son of Abraham to fulfill His mandate. The Lord will “multiply him greatly” (v. 20).

This blessing, of course, cannot compete with the destiny God has for Isaac. For the third time God declares His covenant will be with Sarah’s son (v. 21), so that Abraham will never forget the Lord’s grace that was revealed in Isaac’s birth. This Isaac will be the son through whom Abraham fathers many peoples (v. 16) — not only one nation as in the case of Ishmael. Moreover, while certain divine blessings are given to Hagar’s son, it is Isaac who finds salvation (21:9–21; Gal. 4:21–31). Sarah’s son will be the first of Abraham’s offspring God uses to bring to pass His word concerning the patriarch.

Yet, Isaac will not be the only son of Abraham the Lord will use to accomplish His purposes. It is no mistake that later saints such as Samuel (1 Sam. 1:1–20) and John the Baptist (Luke 1:5–25) find their origins in similar circumstances — born to mothers who apart from God’s special grace were unable to conceive. In favoring Hannah and Elizabeth, God would have us recall the birth of Isaac and be reminded of His gracious election and power, which alone can guarantee the blessing of Abraham will come to His people.

Coram Deo

We are reminded that salvation is wholly from God when we see the many miraculous births in Scripture. Of course, the preeminent example of this is Jesus’ nativity, as He was conceived by the power of the Holy Spirit and born of the Virgin Mary. This same Spirit is given to all who believe on Christ to empower them to live unto holiness (1 Cor. 12:13). If you are a Christian, be encouraged that the One who has saved you is the One who empowers you to serve Him.

For Further Study