Sometimes people go around “confessing” things in “faith” that aren’t true, and such words have no effect. There is, however, someone who speaks and it is as good as done. As Lamentations declares, “Who speaks and it happens, unless the Lord has commanded it? Isn’t it from the Highest One’s decree that both harm and good issue forth?” (Lam 3:37–38).
When God declared to Abram, “I have made you a father of nations” (17:5), he referred to a future promise. God is referring to what will happen through Sarah (17:15–16), thus to something that in Genesis 17 still remains future. What matters, however, is not whether something has already happened, but whether God has decreed that it will happen. Some promises in the Bible are conditional, of course, but God states the condition here and Abraham follows it.
God’s promise was not only that Abraham would become a father of nations, but that kings would descend from him.
First, God states the promise he makes as part of the covenant (“As for me,” 17:4); God also makes a promise concerning Sarai (“As for Sarai,” 17:15). The condition for Abraham is clear: he and his descendants must be circumcised (“As for you,” 17:9–14).
God’s promise was not only that Abraham would become a father of nations, but that kings would descend from him (17:6). Again, he refers to Abraham’s line by Sarah, through their son Isaac: “kings of peoples” (plural) would descend from Sarah (17:16). Other rulers might descend from Abraham’s lines through Hagar (Ishmaelites), Keturah (Midianites and others), and from Abraham’s and Sarah’s relatives (peoples from Lot’s daughters). From Sarah, however, the only two peoples would be the Edomites and the Israelites. Jacob’s line, like Esau’s (36:31), would include many kings (35:11), most importantly in the Davidic dynasty. But Jacob would beget not only a nation but a community of nations (35:11). The ultimate Davidic ruler, the Messiah, would rule all nations (see Isa 11:10, 12).
Those who genuinely believe what God has promised, however, will readily undertake any conditions to serve and please the God who watches over us
Abraham obeyed his part of the covenant immediately (17:23), despite the pain of circumcision at his age (nearly one hundred, 17:1, 17, 24), and the pain of his followers. They needed a new leader who would succeed him, and this leader was promised by God. Often when God makes a promise there is a condition, and the condition often entails a cost. Those who genuinely believe what God has promised, however, will readily undertake any conditions to serve and please the God who watches over us.
In this chapter, we see God’s covenant faithfulness and his power to bring to pass what he promises. We also see the importance of obeying what God commands.