This battle, if one should call it that, is pretty gruesome but it's God's judgment on Moab, not for the breach of the treaty but for the idolatry.
As the prophet says, they are to chop down all of the good trees, stop up the wells and fill the fields with stones but things get a bit out of hand.
When the king of Moab looked out across that valley he never expected to see water, it's never been there before. So maybe God made it look like blood, perhaps the morning son gave it a red tint or maybe just the reflection where it wasn't expected made him think he saw blood. In any case it caused him to drop his guard and approach an enemy force unprepared. It wasn't much of a battle, Israel, Judah, and Edom were all ready to fight and Moab was not. The slaughter becomes so intense that the king actually sacrifices his own son in sight of Israel as a plea to his god. When things came to this state, Israel wisely leaves. It's not good to deal with people who have gone insane.
Today's workout, Pull. Step, pull-up, hop, hamstring curl, weight swing or climbers, row, skater or step-over, bicep curl.