Whatever your lips utter you must be sure to do, because you made your vow freely to the Lord your God with your own mouth.
In God’s eyes, words matter. Our thoughts reflect our motives and are brought to reality by our words. What we think is what we say is what we do is who we are. Something like that anyway. Those of us who are children of God do what we say because our word is our bond. The heart of a believer is revealed in what is spoken, thus, we must be faithful to keep our word even to our own disadvantage.
Psalms 15:4b
But he honors those who fear the Lord;
He who swears to his own hurt and does not change…
A vow made freely to God is a promise that must be kept. There is no other option for the faithful believer. Our word is our bond.