'Vow' in the Bible

And she vowed a vow, and said, O LORD of hosts, if thou wilt indeed look on the affliction of thine handmaid, and remember me, and not forget thine handmaid, but wilt give unto thine handmaid a man child, then I will give him unto the LORD all the days of his life, and there shall no rasor come upon his head.

And the man Elkanah, and all his house, went up to offer unto the LORD the yearly sacrifice, and his vow.

“As for me, I vow that I will not sin against the Lord by ceasing to pray for you. I will teach you the good and right way.

Jonathan made David vow again out of his love for him, because he loved him as himself.

David made this vow to Saul, and then Saul went home, while David and his men went up to the stronghold.