Bible Dictionary
VOW
A vow is a solemn promise made to God, either to perform something or to abstain from it. Scripture does not require vows, but treats spoken vows as sacred obligations that must be fulfilled carefully.
Biblical Usage
The Old Testament does not require vows as a religious duty, but treats an uttered vow as sacred and binding. Jesus refers to vows to condemn their abuse. A vow was to be fulfilled carefully, not made lightly, and could be affected by a father’s or husband’s veto.