I don’t have definite answers about the Old Testament texts of terror. All I can do is place question marks over them and leave them there. I will not say, as some do, that they are false records of what God commanded invented to justify Israel’s holy wars. I just don’t know how to explain them. But I certainly don’t think they have any relevance for Christians. Jesus not only set aside Israel’s ceremonial laws and practices for his followers; he also revealed a side to God’s character and will only hinted at in the Old Testament (mostly in certain Psalms and in portions of the prophets).
It greatly encourages me to see a New Testament scholar of the first water admit that he doesn’t have all the answers.