Have you ever found yourself, in your prayers, bargaining with God? If You… then I… I think sometimes we're tempted to try to bargain with God because we bargain with each other. How often do we do something for a friend with an expectation of something in return? If you do this for me, then I'll do this for you. None of us wants to owe a debt to someone; we don't want to be in a place of feeling as though someone else has been more generous to us. We don't like the idea of receiving gifts if we don't give something in return. It's the way humans work, but it's not the way God works.
Jepthah thought he could bargain with God. It was a classic "if, then" statement: "If You give me victory, then I will sacrifice the first thing I see from my household." What a foolish bargain! This isn't evidence that God desires for people to sacrifice their children. I don't believe God was pleased by Jepthah's actions. In fact, Jepthah missed the whole point: God was going to give victory anyway. God doesn't bargain with us. We can never earn what He has to give because of our fundamental, sinful, human nature. We are too far from Him. What a tragic ending to this story. A young virgin loses her life because of the stupidity of her father.
Next time you're tempted to bargain with God, my advice is to rethink the situation. God seeks to make His glory known across the earth; He does not bargain with man.