Abram has returned from battle. The king of Sodom offers him the goods if only the people are returned. But Abram refuses. He has lifted his hand to the LORD, God Most High, and will not let the king say later, “I have made Abram rich” (Genesis 14:22–23). The victory must not become the beginning of a new dependence upon Sodom.
Immediately afterward Genesis 15 begins with the word of the LORD: “Fear not, Abram: I am thy shield, and thy exceeding great reward.” Notice how these words follow what has just happened. Abram has refused the goods; God speaks of his protection and reward. Yet this does not mean that every uncertainty has disappeared.
For Abram immediately asks a question: what will You give me, seeing I go childless? His possessions have increased, but the son God promised has not come. The promise of many descendants stands beside the visible reality of his childless household. Abram does not hide his question from God.
Then God brings him outside. “Look now toward heaven, and tell the stars, if thou be able to number them.” Abram can see the stars. But he cannot count them, and the descendants of whom God speaks are not yet visible. He is given no date for the promise's fulfilment. He hears again who is making it.
Then comes that one sentence: “And he believed in the LORD; and he counted it to him for righteousness” (Genesis 15:6). First God speaks. Then Abram trusts. The text does not say that some special achievement of his has brought the promise nearer.
Paul returns to this account in Romans 4 and Galatians 3. He speaks of righteousness not earned as wages for our own works, but bound up with faith in God's promise. We should not detach that apostolic explanation from the story in which Abram asks his questions and hears God's answer.
I find comfort in that. We need not conceal our questions as if they could never belong alongside faith. Our certainty rests, in the end, not on what we can already hold, but on the faithfulness of the One who speaks. Abram does not yet have a son. He has God's Word.