"When you make a vow to the LORD your God, you shall not delay to pay it; for the Lord your God will surely require it of you, and it would be sin to you. But if you abstain from vowing, it shall not be sin to you. That which has gone from your lips you shall keep and perform, for you voluntarily vowed to the LORD your God what you have promised with your mouth" (Deuteronomy 21-23).
It is important that you reveal the breaking of a vow to your confessor father so that you may receive from him absolution and the appropriate admonition and discipline.
"If we confess our sins, He is faithful and just to forgive us our sins and to cleanse us from all unrighteousness" (1 John 1:9).