Let your yes mean yes, and your no mean no. Anything more than this comes from the evil one.
Matthew 5, 37

A friend who lives in a country where the people are very polite to each other. An anecdote says it this way: If one says yes, he means perhaps and when he says perhaps, he means no, and if he says no, he is not from this country …
How good that God does not deal with us this way! His Yes to us is an eternal Yes! If He once said yes to you, forgave all your debt and adopted you as a child, you can do what you want: His yes remains yes. He is faithful, even when we sometimes are unfaithful.
We have to be exactly like God, a yes is a yes, a no is a no. Our children, friends, siblings and colleagues should be able to rely on us. Our decisions should be firm and our no to sin should be a firm resolve and our yes to Jesus an irrevocable and consistent Yes. We do not want to fluctuate on both sides, but are focused and determined and live in our lives. This is easier for ourselves and we can straight go our way.
Let us not be pressured by others to a hasty Yes, but weigh well where we say yes. Then there is no disappointments afterwards. We also do not want to be bound by a vow or oath; a yes or no will do it.

Thank You, Father, You say yes to me! I am Your child and You are my God. You are loyal and You never regret Your vote. You search and care for me when I am unfaithful, until You got me back into Your flock. Thank you, Father, for Your loyalty! Thank you that I can rely on Your word! Thank you that yYou never forget or leave me! Thank you, on You I can rely on!!