"Abraham is looking upon the history of Israel and watching. Will God justify the ungodly? Abraham then finally sees the sending of the Messiah, a day he has been waiting for (John 8:56). Then comes the day of Calvary. "What is it that God is doing? God takes his Son, his only Son, whom he loves, and sacrifices him - the Lamb of God that takes away the sin of the world (Gen. 22; John 1:29).
What, however, are his children doing? "But they kept demanding with loud shouts that he should be crucified; and their voices prevailed" (Luke 23:23). This is the moment of truth: Will God justify the ungodly? (Rom. 4:5) On this Abraham has built his faith.
And it happens: God raises Jesus from the dead - as Israel's Messiah! Now nothing can stop the fulfillment of the promise: All nations will be blessed through his posterity."