Ecclesiastes 5:5

Better is it that thou shouldest not vow The point which the Teacher seeks to press is obviously the optional character of vows. They form no part of the essentials of religion, they are to be deprecated rather than otherwise; but to make them, and then delay or evade their fulfilment, is to tamper with veracity and play fast and loose with conscience, and so is fatally injurious. The casuistry condemned by our Lord (Matthew 5:33; Matthew 23:16-22) shews how fertile was the ingenuity of Scribes in devising expedients of this nature.