Еврейская мысль к Берешит 20:6

In the case of Bileam riding the she-ass, the matter is reversed. A female animal is normally mounted by the male. He who rides the she-ass is saying then that the physical is in charge. Since the physical can be either active or passive, the picture drawn of Bileam is merely that of the interaction of active and passive physical forces. When Abraham is reported as taking the two lads with him, we can picture him thinking that these two strangers were allowed to live, whereas his own son was to die. By including this statement in the narrative, the Torah testifies that this consideration too did not sway Abraham or arouse his parental compassion causing him to question G-d’s command. He split the firewood, so that in the event none could be found at the site of the sacrifice, he would not use that non availability as an excuse to put off carrying out the mitzvah. The answer Abraham gave to Isaac's question "Where is the lamb for the offering?" is a classic. On the one hand, Abraham is able to suppress his compassion, on the other hand, he manages to avoid frightening his son at that moment. All the subsequent steps described, such as building of the altar, arranging the wood pile, binding Isaac, are part of the picture of unfaltering devotion of Abraham to the performance of the mitzvah at hand. Had it not been for the angel who had to call him twice, he would not have stayed his hand. This is why G-d could proclaim, "I know (already) that you are G-d fearing," since the objective of the trial had not been the slaughter of Isaac but the degree of obedience Abraham could demonstrate. (4) The meaning of "now I know" is not the acquisition of a new dimension of knowledge that G-d had not possessed before, but that He was able to demonstrate knowledge of a deed without the deed actually having been performed.