[19] He did not weaken in faith when he considered his own body as (already) dead (for he was almost a hundred years old) and the dead womb of Sarah. [20] He did not doubt God's promise in unbelief; rather, he was empowered by faith and gave glory to God [21] and was fully convinced that what he had promised he was also able to do.
(CCC 2572) As a final stage in the purification of his faith, Abraham, "who had received the promises" (Heb 11:17) is asked to sacrifice the son God had given him. Abraham's faith does not weaken (“God himself will provide the lamb for a burnt offering."), for he "considered that God was able to raise men even from the dead" (Gen 22:8; Heb 11:19) and so the father of believers is conformed to the likeness of the Father who will not spare his own Son but will deliver him up for us all (Rom 8:32). Prayer restores man to God's likeness and enables him to share in the power of God's love that saves the multitude (Cf. Rom 8:16-21).
