12 Above all, my brothers, do not swear—not by heaven or by earth or by anything else. Let your “Yes” be yes, and your “No,” no, or you will be condemned.
Our words need to match our actions. If we say we are going to do something, then we had better do it. If we don’t, then we are demonstrating that we are not walking with God as we should be walking. Our claim and our walk don’t match. This does not mean that we always give vague commitments to other people, just in case we need to slip out at the last minute. Some cultures around the world will never say “No” to your face. They will always agree with what you are saying when you are present. They will verbalize a commitment to do what was discussed, but then do something very different. This way of acting is definitely not in line with the message of the Gospel. Our words need to be straight forward and direct when it comes to making commitments. “Yes” and “No” are great words to use. But our words and our actions need to match. Some people out of guilt say “Yes” to everything they are asked to do. Then they run their lives ragged in an attempt to keep all those commitments. And of course there are some of those commitments that they are unable to keep. If you are one of those people, you need to learn the art of saying “No”. We cannot do every task that exists. We must be sensitive to the prompting of the Holy Spirit so that we commit to those things He is leading us to do. If I did everything I was capable of doing, I would run myself ragged in short order. I play instruments, sing, arrange music, preach, teach, counsel, train, develop training materials, build cabinetry, refinish furniture, landscape…. As you can see, if I did all those things I would have no time to do other things that are more important like being a good parent and spouse. If I fail at being a good husband to my wife, I have failed at all the other tasks.
The Arnold Journey 