In context
19His faith did not weaken when he took stock of his own body, as good as dead—he was about a hundred years old—and of the deadness of Sarah’s womb. 20He did not waver at God’s promise in unbelief; his faith made him strong, and he gave glory to God, 21fully convinced that what God had promised, God was able to do. 22That is why it was counted to him as righteousness. 23And the words “it was counted to him” were not written for his sake alone;
