What does Romans 4:18 mean?
God credited Abraham with righteousness because of his faith. Paul has been using this as a strong example of God's plan for human salvation: one grounded in faith and belief, not in our good works or legalism. One of the things Abraham believed God about was that he and Sarah would have a son. This was not a sensible belief, looking from a purely humans perspective. Abraham and Sarah were outrageously far beyond the age when human beings are capable of having children. And yet, in the end, God honored that faith by providing them with a son, Isaac (Genesis 21:3).Paul says here, though, that in hope, Abraham believed against all hope, that not only would he finally have a son with Sarah but that God would keep the promise to make him the father of many nations. Paul quotes that promise from Genesis 15:5. As Abraham looked up at the starry host of heaven, God told him, "So shall your offspring be."