Rav Gidel said in the name of Rav, “From where do we learn that one may make an oath to fulfill a mitzvah? From the verse, ‘I took an oath and I will keep it, to guard the judgments of Your righteousness’ (Tehillim 119:106).”
The apparent meaning of this teaching is that one may make an oath to fulfill a mitzvah, and the oath that he makes is binding. However, the gemara asks, “But isn’t he already under oath to fulfill all of the mitzvahs from the time of the giving of the Torah at Sinai?” At that time, the entire Jewish People promised, “We will do and we will hear” (the Torah and commandments). How can a person make himself more under oath and more obligated than he already is?
The answer offered in the sugya is that the person may make an oath in order to be more inspired and invigorated to fulfill the mitzvah properly. The Maharsha explains that this oath is in fact not binding, but is permitted nevertheless (and is not considered “taking Hashem’s Name in vain” — see Rabbenu Asher). The Rishonim discuss and express differences as to whether this oath is binding, and, if so, to what extent — see Rabbenu Nissim, Tosefot, Ramban and others.
The Maharsha also explains why the gemara asks about the “redundancy” of the oath specifically on the teaching of Rav Gidel in the name of Rav, but did not pose this question directly on the verse that is the basis for the Sages’ teaching. From the verse, says the Maharsha, I might think that that the oath mentioned is the one made by the entire Jewish People to keep all mitzvahswhen they received the Torah at Mount Sinai, and King David is “reaffirming” in the verse that he will fulfill the oath made at Mount Sinai. Only after Rav Gidel in the name of Rav explains the verse to be teaching about making a new oath to fulfill a mitzvah, the gemara can challenge this teaching by saying: “But he already made this oath at Sinai!”
Rav Gidel said in the name of Rav, “One who says ‘I will get up early and learn a certain chapter or a certain tractate’ has made a great vow to the
Although this promise that the person makes does not contain the Name of Hashem, it nevertheless has the status and strength of an oath since the person is making a statement of commitment to do a mitzvah. Just as when a person who states that he will give charity is considered to have made a binding commitment, likewise a person who declares intent to learn Torah (beyond the minimum) is bound by his statement as “a great vow to the
Hashem, we do not suspect that he intends to learn Torah for his own personal honor and self-aggrandizement to be called “Rabbi.” Rather, it is assumed that his aim is to learn Torah “for the sake of Heaven”. (Maharsha)
- Nedarim 8a