As it is written, “ I have made you (Abraham) a father of many nations.” He is our father in the sight of God, in whom he believed - the God who gives life to the dead and calls things that are not as though they were.
Abraham was really old. He’d been married to Sarah for many, many years. She never conceived.
He had taken his destiny into his own hands, at one point, and gotten himself a son through Hagar, Sarah’s maid.
So, how can it be said that his faith was credited as righteousness?
Because, God, in his grace, didn’t snatch his blessing away because of Abraham’s sin. God remained faithful even after Abraham’s faith failed him!
God pointed out Abraham’s failure, but he didn’t hold it against him, and , when God told him Sarah would still be a mother, despite his sin, he believed him!
“…and calls things that are not as though they were.” Calling is a creative act for God. It’s not calling a chair a chair because it is one. It’s calling things into existence, which only God can do.
Abraham knew that nothing is called into existence by the word of man. But he knew that God was the Creator, and that the Word he called into existence was a New Word.
Because he forgave Abraham, a whole nation, a whole people group were called into existence that hadn’t been there before. Because God forgave him, he became the “father” of the Messiah!
A new thing! Something that was not, but then was. (Moses and the law) Something that was not and now is! (the New Covenant)
Before Isaac was conceived, Abraham blew it. He fathered a son that was outside the promise. And the consequences have certainly been far reaching.
But God is even using that to bring his kingdom to earth. it is part of the tapestry. It is part of the beauty of his plan.