There is probably a tendency for us to replace the biblical characters we encounter in the text with ourselves, and to assume certain unchangeable conditions common to our personal experience (and era) were the very same, in all respects, in those ancient days. We should be content and thankful that so much of our human nature is the same, so we are able to relate quite well to ancient figures. But at the same time, we need to allow for variation and distance between the ages resulting in "strangeness," an exotic quality that forces us to reckon with the reality that we are engaging with an alien culture.
For all our remove from Abraham's day, and the fact our revelatory possession (in the Bible) is contained as opposed to open ended and "live," truthfully the advantage is ours, in that we "have the prophetic word made more sure," to use Peter's phrase. Abraham is such a towering figure of faith (as Paul describes him) in part because his written possession of divine revelation in permanent form was tiny. We don't know how much he had, but if what he could hold in hand was equivalent to the first half of Genesis, then it was spare indeed.
What did he have? He had revelation in nature, which included the moral law, and some divine promises, either directly revealed to him or possibly conveyed to him from an earlier generation in written form. To this extent, we may reason to observe that Abraham would know life was precious, it was God's gift, and not to be reaved apart from justice by one man from another.
The question we're asking ourselves in this thread is: based on Abraham's character (we think), given the crime of murder and aggravations like the nearness of kin in this case and the uniqueness of the seed of promise, wouldn't Abraham doubt the command given him by God? Another question: would someone in possession of an accurate assessment of the divine character believe a command from heaven that (we think) appeared immoral and unworthy of God?
What are our unexamined assumptions, in those cases? Perhaps they begin thus: that a command from the Living God to take the life of someone--especially the promised seed--absent any explanation of the justice of the demand in terms Abraham and later generations could grasp (including ourselves) is indistinguishable from a prompting from the devil. Is this true? The text alone seems clearly to indicate that Abraham harbored no doubt that El Shaddai, the same God of promise who fulfilled that word in his son, gave him his new sacrificial direction.
We are used to hearing horror stories from maniacs on trial or reported of them in the news, that these folks claim to hear voices that told them to kill. We superimpose those tales on Gen.22. We reason that the maniac in the news is wrong and his acts evil, and either nuts or faking it, because thinking God is summoning a man to annihilate others is self-evidently contrary to the moral law of God.
A bare command purportedly direct from God is not sufficient to compel action, and is not a defense acceptable at the bar of justice (or Justice). The killer obeying the voices in his head, which he has separated from his own internal monologue as a kind of coping mechanism for his base desires, is not comparable to Abraham and the revelation that came to him concerning the sacrifice of Isaac.
In the first place, Abraham had many other divine encounters prior to Gen.22; if he had begun with any uncertainty that the Living God treated with him, such uncertainty had been overcome many decades earlier. God had both appeared to him and spoken to him, and his word had been verified time and again. We might say Abraham was as steeped in familiarity with divine revelation (on terms suitable to his situation) as many of us are who have decades of familiarity with special and general revelation available to the average Christian in the west, including reading the Bible ourselves and countless good quality Sunday sermons.
Mockers may say Abraham was simply "hearing voices," but his testimony (which is what comes down to us from him, and from Moses in the form of the text of Genesis) is to the contrary. Whatever reason we have to believe the mockers, based on shared skeptical worldview or common culture, we have better reason to believe Abraham's version of events. God had already given Abraham sufficient reason over a long time to trust that anything he was commanded by God to do was legitimate and right, even if it had a surface implausibility based on other criteria.
Furthermore, on this occasion we are compelled to conclude that Abraham was sufficiently justified (even if we do not know preciesly how so) in rejecting the suggestion that the devil must be masquerading this time as the angel of light, pretending to be the agent of the divine word. Maybe we need nothing more than confirmation through the author of Hebrews (11:19) that he was moved to believe in a resurrection upon receipt of the astonishing order. He correctly judged this hope was consistent with all the previous revelation he had of God.
Therefore by several strands of reason, it was impossible for him to doubt God was testing his servant, and he had the duty to obey the external Voice, not a voice forged of his imagination. For our part, we must accept Abraham's version, Moses' version, the Holy Spirit's version, in preference to a naturalistic interpretation, or a comparative-religion interpretation. "Human sacrifice" is and ever has been abominable; therefore, Abraham was not preparing to perform human sacrifice in the standard definition of that term.
God took on flesh, and sacrificed himself--a human sacrifice. Even men acknowledge a great difference between human sacrifice as a grotesque act of devotion (to idols and the devil), and a sacrificial laying-down of one's own life for his friends, or for a righteous man, or (as deplorable as it may be) when some lives are regarded as expendable for the sake of other lives. God had a morally sufficient reason--even if he never explains himself to us--not out of character in himself or as he is free to command men what he will, to bid Abraham make this sign of his only and beloved son (Gen.22:2) through his death.
If it is hard for us to imagine being in Abraham's place, I don't suggest it was easy for Abraham; whether to commit to the act or to nearly carry it out, regardless of what he thought would be the outcome after the fact. We don't have to replay Abraham's severe act. We don't have to try to psychologize the mind of Abraham before he saw the end of his faith.
What Abraham ended with, we also receive without the attendant suffering he went through. We accept the limits on our effort to put ourselves in his sandals, and we accept the extravagant blessing of graciously being put in possession of the whole saga; not confined to the stories of Abraham and Isaac alone, but as those stories proved part of the full story of redemption. We are of the faith of Abraham.
