Abraham's accounting, described in Hebrews 11:17-19, reveals how he reconciled God's promises like a bookkeeper adding up evidence. Based on his long fellowship with God, Abraham knew God cannot lie, tests no one beyond their ability, and possesses creative and resurrecting power. Since Isaac was the promised heir through whom the covenant would continue, Abraham concluded that God would either raise Isaac from the dead or provide a substitute. This reckoning enabled him to proceed toward Mount Moriah, treating the act as accomplished. The same accounting explained his earlier obedience in departing without knowing his destination. Abraham consistently moved forward on sufficient evidence, valuing his relationship with God above the land or Isaac, thereby passing the supreme test. Also see sermons and articles about 'Abraham, Accounting of'.
Hebrews 11:17-19 By faith Abraham, when he was tested, offered up Isaac, and he who had received the promises offered up his only begotten son, of whom it was said, "In Isaac your seed shall be called," concluding that Godwas able to raise him up, even from the dead, from which he also received him in a figurative sense.
Romans 4:19-22 And not being weak in faith, he did not consider his own body, already dead (since he was about a hundred years old), and the deadness of Sarah's womb. He did not waver at the promise of God through unbelief, but was strengthened in faith, giving glory to God, and being fully convinced that what He had promised He was also able to perform. And therefore 'it was accounted to him for righteousness.'
James 2:23 And the Scripture was fulfilled which says, 'Abraham believed God, and it was accounted to him for righteousness.'And he was called the friend of God.