Numbers by Moses — Read

Then Moses spoke to {the leaders}[note: Literally "the heads"] of the tribes concerning the {Israelites},[note: Literally "sons/children of Israel"] saying, "This [is] the word that Yahweh commanded:

if a man makes a vow for Yahweh or swears an oath with a binding pledge on himself, he must not render his word invalid; he must do all that went out from his mouth.