We once again find ourselves hearing about the life and times of Elisha as he leads Israel into the conquest of the Arameans and into a time of famine followd by a miraculous defeat of the Arameans simply by them running away and leaving all of their provisions behind without even a battle.
We then transition to Jehu who cleans house, literally, and removes the king of Iarael and and all of his family and all of the family of Ahab including his wife, Jezebel. Remember Ahab and Jezebel, the two who fought against Elijah on Mt. Carmel but were defeated by God bringing fire down? Yeah, she is still around as well as the children of Ahab, 70 of them, and each with some right to the throne. With the elimination of them Jehu is able to lay claim to the throne after Elisha sends his servant to go and annoint him.
As a reult Jehu kills all the prophets of Baal and destroys the temple of Baal while at the same time still hung on to the sins of Jeroboam and was willing to worship not just God, but also the golden calves of Bethel and Dan. Even though he cleaned house in a very effective way, old bad habits die heard, and that still tripped him up.
Psalm 140 speaks of those who would use violence to bring about their desires and prays that their plans would not succeed. It is somewhat ironic to hear about Jehu who is supported and encouraged by the Lord and the degree of violence that is a part of his life and yet he is doing God's will. Not somethign that in our modern day we would consider the way to do things at all, and Psalm 140 reflects that, but historically we simply know that God's people took over control through violence primarily. When Jesus came along he changed all that.