The story of Abraham and Isaac is at least 3500 years old. Why should I, and we, still be interested in it? I believe that the story represents an archetype of what constitutes effective punishment. An archetype is a pattern of behaviour programmed into our genetic make-up which must be satisfied if humans-as-species are to be satisfied with the outcome. The Abraham story (is it a myth?) represents what humans-as-species accept as effective punishment.
Punishment is effective when the offending behaviour ceases, the harm-doer is sorry, the victim (in this case God, who expected better) satisfied, and the relationship between the two rehabilitated. The harm-doer sins by behaving in an unrighteousness (and un-benevolent) way. S/he is judged and punished. S/he sincerely repents and is forgiven. Through forgiveness, s/he is redeemed (or rehabilitated). This is the story of Abraham and God.
God has faith that even though Abraham has sinned, he will be redeemed through his willingness to repent. And God is proven a good leader because he is willing to forgive Abraham and give him another chance. This story describes how punishment can be made effective through restoring harm-doers to righteousness.