Jehoshaphat of Judah joined forces with Joram of Israel and the king of Edom to fight against Moab. The Bible says Jehoshaphat did what was right in the eyes of the Lord, but Joram did evil in the eyes of the Lord. So was fighting against Moab the right thing or an evil thing to do, in the eyes of the Lord?
Well, according to Joram, God had called those three kings together into this conflict with Moab. Maybe you don’t think Joram’s opinion is reliable, since he’s the evil king here, but God’s prophet Elisha agrees with him. It says the Israelites invaded Moab and slaughtered the Moabites, and according to Elisha they were able to do this because God delivered Moab into their hands.
Another story about Jehoshaphat makes it even more clear: God sent good king Jehoshaphat to march against the Moabites in God’s battle against them. Jehoshaphat didn’t end up actually fighting the Moabites this time, but only because God did it for him.
Balaam, a prophet of God who could say nothing but what God told him to say, declared that Israel would crush Moab, with no indication that that would be a bad thing. When Isaiah predicts that the Israelites will subdue Moab, the context seems to imply that they’re doing it with God’s blessing. And the prophet Zephaniah said God decided that Moab would be destroyed for mocking God’s people, and his people would plunder Moab and take over their land.
God sent Ehud to defend Israel against Moab. When Ehud killed the king of Moab, he described it as delivering a message from God. And then he declared that the Lord had given Moab into the hands of Israel.
Then there’s David, who always did everything God wanted him to do. One of the things God wanted him to do, apparently, was to defeat the Moabites. And then arbitrarily kill 2/3 of his Moabite captives.
So clearly God approves of his people fighting against the Moabites. Why wouldn’t he, when that’s something he does himself? God is perfect, and everything he does is right, so this must be a good example to follow.
On the other hand, the Bible says back in Moses’s time God told his people not to harass the Moabites or provoke them to war, because he didn’t intend to give Israel any Moabite land. So all that other stuff the Bible said must be wrong.