Abraham believed what?

Genesis 22 is a test of Abraham's faith, right? Nothing simpler than that, is there!
Sorry. Wrong.
Perhaps parenthood makes a passage like the offering of Isaac harder, but I think attention to detail sometimes forces a more careful consideration of the passage, and given that the Amateur is an amateur, sometimes the way is blocked.
Here's some mysteries in Genesis 22:
1. Why is Abraham so convinced that he'll get Isaac back (v5 and v8 - see also Hebrews 11), yet he goes all the way to placing Isaac on the altar?
2. Why does God test Abraham in this way? I'm afraid the "it's seeing how much Abraham will give for God" simply won't do for me anymore. Firstly, I am convinced that the God of Genesis 22 is the God of the entire Old Testament, a God who very clearly condemns all child-killing and especially child-sacrifice. Why does God seem to go against His own very clear standards. Again, don't tell me that the Law had not been given at that stage. God's opinion on moral questions cannot change, otherwise we'd end up with a God who is not perfect in wisdom. Secondly, God is actually asking Abraham to destroy the covenant - the fulfilment and blessings of which have been explicitly tied to Isaac(17:19,21 and 21:12). If Isaac is lost, then so is the covenant.

Here's my solution, for what it's worth. I think Abraham's faith is being tested in two ways, a surface way and a deeper way. On the surface is the basic test, Abraham's passing of which is acknowledged in 22:12. Abraham was willing to do whatever was commanded. But on a much deeper level it is actually the faith of verses 5 and 8 which is commended, the faith that God keeps His promises, the faith that knows God is not the child-killer that the pagan gods were, the faith which said whatever might happen on the mountain the Lord would show him, God wasn't going to lose Isaac. You see, we are called to be people of visible faith, faith that obeys; yet it is the faith that knows God and trusts His promises that is the faith for which Abraham is commended in Genesis 15, and which is commended in Romans 4 and Galatians 3, then unpacked and related to this passage in James 2. That faith is the one to which we are actually called here.

So, what is a sacrament after all?

Dear me, not figured it out yet? After all, I am an amateur. There is a huge difference between an amateur and a professional. Primarily that thinking is a luxury for me for which I seldom have time.
When earlier in the year I was reading Genesis, I was struck by the sacramental nature of covenant relationship. Noah gets a rainbow, Abraham gets a sighting of the land, gets circumcision, gets that ritual with God walking through the cut animals, and Jacob gets his ladder. Each time God acts, He provides a sign of that of which He has spoken, which is symbolic, that is, it is itself illustrative of the promise, and which is also a seal, a guarantee of that of which God has spoken. When the patriarchs acts in faith, they find God truly faithful to these promises.
Here's my problem: the idea of a seal. Faithlessness delays divine action, but He works out His purpose in the end. So here's the big issue: are baptism and Communion given to the church, signs symbolic of His work among us which all visible members receive (fine, happy so far) and seals that He does so act among us. Or are they seals to the individual as well? If so, what is the role of faith? "Do those without faith also receive the signified?" - the great Reformational debate - still ought be discussed after you've dismissed substantial interpretations of sacraments (Roman, Lutheran and Zwinglian) for covenantal ones (Reformed). I hope that the book I'm reading at the moment, by Leonard Vander Zee, clears that one up for me.