A Powerful Tefillah
The Gemara in Nedarim expounds the earliest recorded example of hataras nedarim. Hashem told Moshe Rabbeinu that it was safe for him to return to Egypt “because the men who seek your life have died.” The Gemara explains that these men were none other than Dasan and Aviram. However, the Gemara records another implicit message in Hashem’s statement. The fact that the men, who Moshe Rabbeinu had reason to fear, had died, could be the basis for releasing Moshe Rabbeinu from his vow.
Moshe Rabbeinu swore to Yisro that he would not return to Egypt without his permission. In actuality, Yisro consented to Moshe Rabbeinu’s return. Yet the Nimukei Yosef explains that there was a double oath. The first part was the aforementioned oath. Additionally, Moshe Rabbeinu swore without reservation not to return to Egypt at all. It was this second oath that required annulment. Hashem advised and taught Moshe that this new circumstance can be used as a basis for releasing him from his vow.
Still, the Gemara does not record who actually was the sage that released Moshe Rabbeinu from his vow. The commentator on the side of the Gemara, which is identified in the Vilna Shas as Rashi (but surely isn’t), suggests that Moshe Rabbeinu released himself from his own vow. The Bach is tremendously bothered by how the commentator could suggest such an outlandish idea. He is forced to conclude that there is a textual error in the commentary. However, the Shaar HaMelech suggests that perhaps, in a select few situations, a sage can actually permit his own vow.