Then the word of the LORD came to Samuel, saying, "I regret that I have made Saul king, for he has turned back from following Me and has not carried out My commands." And Samuel was distressed and cried out to the LORD all night. 1 Samuel 15:10-11
Because of Saul's disobedience in the previous few verses, the Lord came out with an indictment against Saul, about as strong as you'd ever want to hear from Almighty God. It was distressing even to Samuel. But what was Samuel's response? He cried out to the Lord all night.
What were his prayers like? What did he say to God about Saul? How did he pray? Somewhere along the line, he got some sleep because the next verse stated that he got up to go see Samuel. I suspect that Samuel's prayer focused on seeking God's mercy mainly. He probably sprinkled in some kind of request to give him the right words to say to Saul, then went right back to seeking God.
When's the last time we sought God so diligently, staying up all night to do it? When's the last time we became passionate about God's passions (in Saul's case, it was disobedience)?
And yet, there's another truth we can take from this passage: God was passionate about Saul being obedient to Him. Saul didn't do exactly what God had commanded. And God regretted installing Saul as king. But God is passionate about other things as well. I think he's passionate about truth and justice. He's passionate about drawing men and women to Himself. I think he's passionate about the senseless slaughter of the innocent unborn.
Take a few minutes to ponder other things that God is passionate about. Then pray to ask God to give you that passion as well.