"A father of many nations have I made you," said God to ancient Abraham. We don't know his mental or physical health, but we do know this much -- the old patriarch, now about 100 years of age, cannot begat a child. Even if he could, his wife Sarah, past 90 herself, cannot contribute to the process.
But there is a third character in this scenario, and that makes all the difference. It is God. Not just any god. Not even a fertility god, such as the Canaanite baals. This is Jehovah God, the Creator of heaven and earth. The God who "gives life to the dead and calls into being that which does not exist" (Rom. 4:17).
When this God promises something -- even something so patently outlandish as Abraham becoming father of many nations -- Abraham listens. More than listens. He says "Amen" to God's promise. He "believed" God -- and the Hebrew word for "believe" eventually becomes our English word "Amen." If God promises something, God will bring it to pass. If he created the universe out of nothing, he can call a nation into being if he sees fit to do so -- even from an aged couple far too old to have a child.
God promises Abraham that his descendants will be as the stars of the sky in multitude. Abraham believes God's promise, although he and wife Sarah are childless and very old. And God says, in effect, "That is all I need from you, Abraham. An 'Amen.' Your acquiescence in my promise. Your willingness to act on the basis of my promise, totally trusting me to accomplish what seems humanly impossible. That is all I want and need from any of my human creatures. You believed me, Abraham. You are in right standing with me!"
Then God who called the universe into being empowered Abraham and Sarah to have a son, whom they named Isaac. And when Isaac was older, God tested Abraham's confidence in God one more time. "Go offer your son as a sacrifice," he commanded the old patriarch. And, without hesitation, Abraham set out to do as God said. "God who calls things into being," he reasoned, "can surely also raise the dead. God promised to make me father of many nations. He must plan to raise Isaac from the dead. In a sense, he was raised from the dead in being born, for both his parents were as good as dead so far as producing offspring!" (Gen. 22:1-19; Heb. 11:11-12.)
Abraham's faith was more than mere profession. He really trusted God to do the impossible. Because he trusted God, he entrusted himself to God. Because he truly entrusted himself to God, Abraham quickly set out to obey God. And his good works tangibly "justified" Abraham's profession of faith (James 2:20-24).
The same God who dealt with Abraham speaks now to us. "My Son died because of your sins and was raised again because of your declaration of acquital," God tells us in the gospel. "I will count anyone in right standing with me who truly says 'Amen' to those realities." (See Rom. 4:23-25.)
"How can this be?" we ask. "Surely we must contribute something!" But no. This God calls into being what does not exist. He did not make the universe from spare parts. He does not need our contribution to make us righteous. God simply pronounces us righteous -- us, who have no righteousness and no right to be called righteous. And when God calls us righteous, we become righteous. Only God can perform such a feat. We must trust him entirely to do it. We cannot contribute anything to it. We can only say "Amen!" to God's gospel promise.
When the God who speaks into being what does not exist promises to love us and to forgive us for the sake of Jesus Christ, we can say with absolute confidence, "Amen, God!" And when we do, God says, "I pronounce you righteous and, by my saying that, I make you what I call you."
For more on saving faith, click here.