Step 1: Make the movement of infinite resignation. Give up on your dream. You tried, you failed, accept it, move on, success would be absurd.
Step 2: Make the double movement of faith. Your success would be absurd, you understand that but you believe in it anyway, hoping against hope, living in the promises of God in absolute defiance of reason.
God tells you to kill your son, but also believe the contradictory position that through him you will have numberless descendants? All good. Resign yourself to losing your son and accept that God's promise will return void, that's the first movement. Then reject that, and believe God's promise anyway, despite the order to kill your son. It doesn't make sense. It's anti-intellectual. You're believing by virtue of the absurd. That's a knight of faith.