"Abraham did not deny his son to God. In exchange, God said, Because you have done this thing and you did not withhold your son, your only one., [t]hat I will surely bless you, and I will greatly multiply your seed as the stars of the heavens and as the sand that is on the seashore, and your descendents will inherit the cities of their enemies (verses 16-17). This was the kinyan chalipin, a legally binding transaction based on an exchange of property. You give Me your son, and I will give you your future. And once the kinyan is made, it is an agreement and a covenant that can never be changed. When we say "the God of Abraham, the God of Isaac, and the God Of Jacob," we do not mean God should love us because He loved Abraham. We say that He should love us because he singed a binding agreement with Abraham that requires Him to love us. (The Lord is Righteous in All in Ways, p 53) - Mesoras HaRav Chumash, Bereishis, p. 155.