All about making vows. I am fairly certain that most of us at one time have tried to make a deal with God. If God would do something then we promise to do something in return. That's wrong on several levels. First God doesn't need us to do anything, He's God and He's in control of everything.
That said there are times when God wants us to do stuff. But making vows usually come back to haunt us. Jesus told His disciples not to make vows or promises because He knew they couldn't keep them. On another level, when we accept that God loves us then we must also accept that He wants what's best for us. Bargaining isn't love, it's rewards for behavior. I taught my sons at an early age that when they do what's right things usually work out better, but that has nothing to do with love. Love can't be conditional or it's not really love. God doesn't need us to promise Him anything, He just wants us to love Him as He loves us, there's no pressure on performance.