'Vow' in the Bible

And Jephthah voweth a vow to Jehovah, and saith, 'If Thou dost at all give the Bene-Ammon into my hand --

and it cometh to pass at the end of two months that she turneth back unto her father, and he doth to her his vow which he hath vowed, and she knew not a man; and it is a statute in Israel: