"But what think ye? A certain man had two sons; and he came to the first, and said, son, go work today in my vineyard. He answered and said, I will not: but afterward he repented,and went. And he came to the second, and said likewise. And he answered and said, I go, sir: and went not. Whether of them twain did the will of His father?" Matthew 21:28-31a
I love this passage because it is proof of how sensible and perfect God's ways are. The first son said he wouldn't go, but did, and the second son said he would go, but didn't. I wish people would do what they say they are going to do. I would venture to say there are a lot more people that say one thing and do another. A lot of people are guilty of acting like they like us but inwardly they are plotting to exclude us; acting like they will be there for us, but not showing up when things get tough; acting like they are devoted, but secretly finding ways out of responsibility. Alcoholics are like that and many people Jesus met were like that to.
When Jesus asks which one of the two men did the will of the Father, it is clear that lip service is not the qualifying agent. Doing the will of the Father must be done by our mind and body working together to do whatever we are called to. It's easy to get real spiritual and try to accomplish the will of God with mental assent, but it is not Biblical. God wants us to hear the call, answer the call and do the task, that's truly cooperating with God. Next time you hear God calling you, try to remember this simple rule; He called you because you are the one person in all creation designed to work perfectly in His will to get the job done.