Sanhedrin 89b
God said to Abraham: “Please take your son, your only, whom you love, Isaac” (Genesis 22:2). When God said: “Your son,” Abraham said: I have two sons. When God said: “Your only,” Abraham said: This son is an only son to his mother, and that son is an only son to his mother. When God said: “Whom you love,” Abraham said: I love both of them. Then God said: “Isaac.” And why did God prolong His command to that extent? Why did He not say Isaac’s name from the outset? God did so, so that Abraham’s mind would not be confused by the trauma. Satan preceded Abraham to the path that he took to bind his son and said to him: “If one ventures a word to you, will you be weary…you have instructed many, and you have strengthened the weak hands. Your words have upheld him that was falling…but now it comes upon you, and you are weary” (Job 4:2–5). Do you now regret what you are doing? Abraham said to him in response: “And I will walk with my integrity” (Psalms 26:11). Satan said to Abraham: “Is not your fear of God your foolishness?” (Job 4:6). In other words, your fear will culminate in the slaughter of your son. Abraham said to him: “Remember, please, whoever perished, being innocent” (Job 4:7). God is righteous and His pronouncements are just. Once Satan saw that Abraham was not heeding him, he said to him: “Now a word was secretly brought to me, and my ear received a whisper thereof” (Job 4:12). This is what I heard from behind the heavenly curtain [pargod], which demarcates between God and the ministering angels: The sheep is to be sacrificed as a burnt-offering, and Isaac is not to be sacrificed as a burnt-offering. Abraham said to him: Perhaps that is so. However, this is the punishment of the liar, that even if he speaks the truth, others do not listen to him. Therefore, I do not believe you and will fulfill that which I was commanded to perform. The Gemara cites an alternative explanation of the verse: “And it came to pass after these matters that God tried Abraham” (Genesis 22:1). Rabbi Levi says: This means after the statement of Ishmael to Isaac, during an exchange between them described in the verse: “And Sarah saw the son of Hagar…mocking” (Genesis 21:9). Ishmael said to Isaac: I am greater than you in the fulfillment of mitzvot, as you were circumcised at the age of eight days, without your knowledge and without your consent, and I was circumcised at the age of thirteen years, with both my knowledge and my consent. Isaac said to Ishmael: And do you provoke me with one organ? If the Holy One, Blessed be He, were to say to me: Sacrifice yourself before Me, I would sacrifice myself. Immediately, God tried Abraham, to confirm that Isaac was sincere in his offer to give his life.
Sanhedrin 39b
§ The Gemara cites a verse concerning the king of Moab: “Then he took his eldest son, who should have reigned in his stead, and sacrificed him for a burnt offering upon the wall; and there was great indignation against Israel, and they departed from him and returned to their own land” (II Kings 3:27). Rav and Shmuel engage in a dispute concerning this. One says: The king sacrificed his son for the sake of Heaven, and one says: The king sacrificed his son for the sake of idol worship.
Taanit 4a
The Gemara interprets each phrase of this verse: “Which I did not command,” this is referring to the son of Mesha, king of Moab. King Mesha sacrificed his son, as it is stated: “Then he took his firstborn son, who would reign after him, and he offered him as a burnt-offering” (II Kings 3:27). “And I did not speak,” this is referring to Jephthah, who sacrificed his daughter as an offering. “Nor did it come into my heart,” this is referring to Isaac, son of Abraham. Although God commanded Abraham to sacrifice Isaac, there was no intent in God’s heart that he should actually do so; it was merely a test.