The Genesis 22 episode, often referred to as the Akedah (Aqueda) ie "the binding" is a topic worthy a masterclass in textual and theological development. A comprehensive discussion regarding this development would involve volumes and still leave much to be uncertain. In short, the internal contradictions the narrative offers as it appears in Genesis have inspired millennia of interpretive expansions and elaborations. The apparent contradictions involve the promise for Isaac's future, the command to offer him as sacrifice and the subsequent command not to.
Itis my opinion that these contradictions arose as the result of the incorporation of divergent legends into a 5-6th century composition. Without laboring that point, I'll suggest the story at its core was either an ancient tale that depicted human sacrifice or was a conscious effort to parody that past using the framework and language of such a tale. As a stand alone tale it certainly leaves the reader with confusion. The episode itself ends with the clear impression that Issac was sacrificed and Abraham traveled back down alone:
15 The angel of the Lord called to Abraham from heaven a second time 16 and said, “I swear by myself, declares the Lord, that because you have done this and have not withheld your son, your only son, 17 I will surely bless you and make your descendants as numerous as the stars in the sky and as the sand on the seashore. Your descendants will take possession of the cities of their enemies, 18 and through your offspring[b] all nations on earth will be blessed,[c] because you have obeyed me.”
19 Then Abraham returned to his servants, and they set off together for Beersheba. And Abraham stayed in Beersheba.
The introjection of the voice to halt the sacrifice (an angel/God himself) contributed to the 'second power' in heaven theological development of centuries later, but that is another topic. IOW, many have concluded the story was reworked as part of its incorporation into the Torah.
As we know, theologians such as the writer of Hebrews made interpretive inferences from the story, implying that Abraham understood the resurrection doctrine, which wasn't in the text anywhere. This author was hardly alone in assuming there was more to the story than what the text itself offered. We have preserved for us other retellings of the story that reveal a movement toward the eventual Christian usage as a type of the Christ Son of God sacrifice. That is, the idea that Isaac represented an expiatory sacrifice for the sins of Israel.
The story as it appears in the book of Jubilees (2nd cent. BC) introduces the character of 'Mastemah' (opposer) and his evil angels into the scene, which has the effect of universalizing the episode, giving it greater cosmic significance and it gives Isaac a more active role, giving his consent. It locates the 'mount' as Mt Zion, (aka Moriah, Temple mt.) It also places the episode on the Passover date (17:15, 18:3). Here are some excerpts:
The prince Mastemah came and said in God's presence, 'Look,
Abraham loves his son Isaac and is more pleased with him than
anything else; command him to offer him as a burnt offering on an
altar and see whether he will carry out this order. Then you will know
whether he is faithful in every test to which you subject him' (Jub
17,16).
The Lord knew that Abraham was faithful in all his afflictions,
because he had tested him with a command to leave his country, and
with famine; he tested him with the wealth of kings, and he tested him
again with his wife, when she was taken away from him; and with
circumcision; and he had tested him with Ishmael and Hagar, his
slave-girl, when he sent them away. In every test to which the Lord
subjected him, Abraham had been found faithful. His soul was not
impatient, or slow to act. For he was faithful and loved the Lord (Jub
17,17-18)
The parallel to the opening chapters of Job are inescapable. Again giving a private scene in Genesis a universalizing aspect.
In the Qumran materials was found what has been named 'Pseudo Jubilees' or 4Q225. It is clearly another recension of the book of Jubilees. It retains some interesting variations:
Abraham]
8 be[lieved] God, and righteousness was reckoned to him. A son was born af[ter] this
9 [to Abraha]m, and he named him Isaac. But the prince Mastemah
came
10 [to G]od, and he lodged a complaint against Abraham about Isaac.
[G]od said
1 1 [to Abra]ham, 'Take your son Isaac, [your] only one, [whom]
12 [you lo] ve, and offer him to me as a burnt offering on one of the
[hig]h mountains,
13 [which I shall point out] to you'. He aro[se and w]en[t] from the
wells (10) up to Mo[unt Moriah].
14 [ ]And Ab[raham] raised[his ey]es, [and there was a] fire; and he pu[t the wood on his son
Isaac, and they went together.]
2 Isaac said to Abraham, [his father, 'Here are the fire and the wood,
but where is the lamb]
3 for the burnt offering?' Abraham said to [his son Isaac, 'God
himself will provide the lamb'.]
4 Isaac said to his father, 'B[ind me fast ]
5 Holy angels were standing, weeping over the [altar ]
6 his sons from the earth. The angels of Mas[temah ]
7 rejoicing and saying, 'Now he will perish'. And [in all this the
Prince Mastemah was testing whether]
8 he would be found feeble, or whether A[braham] would be found
unfaithful [to God. He cried out,]
9 'Abraham, Abraham!' And he said, 'Yes?' So He said, 'N[ow I
know that ]
10 he will not be loving'. The Lord God blessed Is[aac all the days of
his life. He became the father of]
11 Jacob (n), and Jacob became the father of Levi, [a third]
generation (12). (vacai) All]
12 the days of Abraham, Isaac, Jacob, and Lev[i were ]
13 The prince Mastemah bound on ac[count of them. Holy
angels were
14 The prince Ma[s]temah, and Belial listened to [the prince
Mastemah.
The subtle intorduction of Isaac's consent is noteworthy. This idea is repeated and elaborated in Targum Pseudo-Jonathan:
And Isaac said to his father, 'Bind me well that I may not struggle in
the agony of my soul and be pitched into the pit of destruction and a
blemish be found in your offering.
This notion of the consent of Isaac is also expressed in Josephus:
(Antiquities 1 .232): 'Isaac . . . received these words [of his father] with joy, declaring that he was not worthy to be born at all if he were to reject the decision of God and of his father.
PseudoPhilo (32:3, 40:2) goes so far as to suggest the notion of expiatory sacrifice for Israel's sins;
..generations will be instructed by my case and peoples will understand because of me that the Lord has considered the life of a
human being worthy [to be offered] in sacrifice.... and who would be sorry to die, seeing a people freed?"
This topic is much larger, but I wanted to open discussion regarding the story and its evolving character. It's usage by Christians, while unique in it's specific application, was not entirely without prior and parallel symbolism. The location of the story to Moriah/Zion (Jerusalem and it's temple), the consent of Isaac, the cosmic importance of the scene involving God's chief adversary, the association with the Passover, even hinting that, like the suffering servant of 2nd Isaiah, Isaac was a symbol of sacrifice for the nation's welfare.