This story tells us two things about God. First, it tells us that God does not necessarily trust his people. Abraham is the one with whom he has made a covenant and yet he tests Abraham in the most painful way possible. Second, it at least implies that God does not actually want human sacrifices.
What this tells us about Abraham and Isaac is that they both trust God. Alternately, you can say that Abraham trusts God and that Isaac trusts Abraham. Either way, Abraham is willing to do what God says because he trusts that God will do what is right. Isaac is big enough to carry the wood up the mountain and yet he allows himself to be put on the wood, ready to be sacrificed. Both of the humans are showing a great deal of trust in this story.