I thought I did address it. At any other time in history the man would have been sinning in stabbing the prophet. But that time, it was just the opposite. It was a sin not to. And there isn't any moral relativism or arbitrariness involved. Just like killing babies. You could go down to Compton or up to SanFran and find a crack house with the same sorts of people or worse than were in Canaan, and it would be a sin to kill their babies. The degree of sin involved has nothing to do with the law against killing babies. God forbids it, just like he forbids marrying a whore or anything else He says to do. If God says to do something, by it's very nature the action isn't sinful, and not arbitrary or morally relative.