But perhaps that's itself the answer. Perhaps Abraham doesn't even think about it. Having moved from an understanding merely of God's power, through an understanding merely of God's justice, Abraham has reached an understanding of God as guarantor of moral order. Abraham may simply have had faith on that day that whatever would happen, it would be consistent with a moral universe. It is hard for us today to have Abraham's faith in a moral universe.
Bad people do bad things to good people, and the press is always there with zoom lenses.
Abraham was God's partner in revealing the world as a morally-ordered place. Today, we can take the next step by being God's partner in creating that place. By behaving morally when it is hard to do so, each of us increases the world's moral sphere, even if ever so slightly. And when all of us behave morally, we can create the world in which Abraham had faith. The mohel was busy that day.