Deuteronomy
Chapter
Deuteronomy is a sequel to Numbers. Narrated in it are three speeches and two poems, spoken by Moses in Moab before the crossing of Jordan, in which he gives the Ten Commandments to the chosen people. A minor narrative in three of the chapters tells of the last days of Moses.
Deuteronomy 23
23:21 When thou shalt vow a vow unto the LORD thy God, thou shalt not slack to pay it: for the LORD thy God will surely require it of thee; and it would be sin in thee.