One of the themes of the High Holidays is the idea of guarding one's speech. In particular, we are to be aware of unfulfilled vows that we may have made. Speech is very powerful and at times biting, insulting words can take years for a person to recover. The words can be like daggers and can be very harmful. By way of a homiletic interpretation, the Rabbis said that one should never make vows, even if he fulfills them. They equated the making of a vow to making a forbidden altar and the fulfillment of the vow, to offering a sacrifice on that altar. It is better to have that vow annulled rather than fulfill it. Realizing the power of speech, vows can be misleading. It may get someone's hopes up in anticipation of the vow׳s fulfillment. And when not fulfilled, there is great disappointment. This is why we do the התרת נדרים ceremony on ערב ראש השנה and this is why we begin Yom Kippur with כל נדרי. We do not want to begin the new year with promises made and not kept.