Numbers 30:7

And her husband heard it, and held his peace at her in the day that he heard it: then her vows shall stand, and her bonds wherewith she bound her soul shall stand.

Cross-reference

Numbers 30:14 confirms that the husband's silence after hearing the vow makes it binding, expanding the same rule from 30:7.

1 Samuel 1:23 shows Elkanah approving Hannah's vow, illustrating the husband's authority to confirm or nullify described in Numbers.