Our Gemara on Amud Beis discusses the status of a person’s possessions, when he declares all of them as Hekdesh, sanctified for the Temple. The Gemara wonders if certain necessities and obligations ought to be exempt, as could he have meant literally everything he owns? The Gemara rules that the clothing of his wife and his children are not included, as we assume he still meant to provide for them and meet his responsibilities toward family.  

The Gemara raises a contradiction to this from a separate teaching (Mishna Arakhin 23b) that rules if a person declares all his possessions to be hekdesh, his tefillin are included. This is a seeming contradiction, as presumably, the same assumption that would exclude his wife’s and childrens’ clothing from being part of his pledge, should also exclude tefillin which he needs for a daily ritual obligation. The Gemara answers that regarding his tefillin, he figures by donating the value of his tefillin, he is doing a mitzvah, so somehow it’s as important as wearing the tefillin. However, donating his wife’s and children’s clothing would cause a quarrel.

The hypothetical person in this rabbinic illustration embodied an ethos where even the mitzvah of tefillin could be secondary to a hekdesh pledge, and yet it is not acceptable to donate materials that are part of his family obligations. The lesson here is, you might believe you are pious by performing a particular mitzvah, but you must be sure it doesn’t interfere with responsibilities to your loved ones.