Pay For Her

The Sofra has a derash on the possuk זאת תורת היולדת (יב:ז) that a man is obligated to bring the korban of his wife even if she is poor.  The Gemorah in a few places brings this principle from Rabbi Yehuda and in Babba Metzia 104a the Gemorah explains his reason is because the husband accepts this obligation upon himself in the ketubah.  From the Gemorah one would get the impression that it is an obligation like any monetary obligation that one accepts upon himself.  However, if that is the case why does the Sofra need a derasha?  What is even more puzzling is that the Sofra concluded with Rabbi Yehuda explaining the obligation is because of the husband’s acceptance of the din (cited in Nedarim 35b,) so why need a derasha?   See the Ritva and Shitta in Babba Metzia as to what the husband’s acceptance of the obligation adds.  However, why do we need the possuk?  The Achronim say that is it was just an obligation because of the התחייבות of the husband then the woman would be considered the owner of the korban and the husband merely donated his animal to her.  The possuk teaches us that the husband is considered the owner of the korban as well (he would be obligated to stay overnight, he could make a temurah etc.)  This would be the point of debate between the Shagas Aryeh #66 and Harav Shaul cited in the Kuntras Acharon if a husband can be obligated in בעל תאחר for the korbanot that his wife is obligated in.  [See Toras Hakodesh #55, Toras Negaim #162.]