Positive commandment · Mitzvat Aseh #95 of 613
Law of the abrogation of vows
לדון בהפרת נדרים בכל הדינים האמורין בפרשה
The verse · Bamidbar 30:3
אִישׁ כִּי־יִדֹּר נֶדֶר לַה׳ אוֹ־הִשָּׁבַע שְׁבֻעָה לֶאְסֹר אִסָּר עַל־נַפְשׁוֹ לֹא יַחֵל דְּבָרוֹ כְּכׇל־הַיֹּצֵא מִפִּיו יַעֲשֶׂה
“If a man vow a vow to the Lord, or swear an oath to bind his soul with a bond; he shall not break his word, he shall do according to all that proceeds out of his mouth.”
The Rambam’s words
To carry out the laws regarding the nullification of vows, as mentioned in the Torah.
לדון בהפרת נדרים בכל הדינים האמורין בפרשה.
Who & when
“And this commandment is practiced in every place and at all times by males, but not by females — as they are not appurtenant to the annulment of vows.”
Where in the Mishneh Torah
Hilchot Oaths הלכות שבועות