Nedarim

It was taught: If one vows by the Torah, his words are of no effect; by what is written therein, his vow is binding; by it and by what is written therein, his vow is binding. Since he states, 'by what is written therein, his vow is binding,' is it necessary to mention, 'by it and by what is written therein?' — R. Nahman answered: There is no difficulty: one means that a Torah is lying on the ground; the other, that [the vower] holds a Torah in his hand. If it is lying on the ground, his thoughts are of the parchment; if he holds it in his hand, his thoughts are of the Divine Names therein.  Alternatively, [both clauses mean] that it is lying on the ground, and we are informed this: even when it is lying on the ground, since he vows, 'by what is written therein,' his vow is valid;  and an anti-climax is taught.  A further alternative: the whole [Baraitha] indeed means that he holds it in his hand, and we are informed this:  Since he holds it in his hand, even if he merely says 'by it,' it is as though he said, 'by what is written therein'. MISHNAH. [IF ONE SAYS,] 'KONAM IF I SLEEP', 'IF I SPEAK', OR 'IF I WALK';  OR IF ONE SAYS TO HIS WIFE, 'KONAM IF I COHABIT WITH YOU,' HE IS LIABLE TO [THE INJUNCTION] HE SHALL NOT BREAK HIS WORD. GEMARA. It was stated: [If one says,] 'Konam be my eyes sleeping to-day, if I sleep to-morrow' — Rab Judah said in Rab's name: He must not sleep that day, lest he sleep on the morrow. But R. Nahman said: He may sleep on that day, and we do not fear that he may sleep on the morrow. Yet Rab Judah agrees that if one says, 'Konam be my eyes sleeping tomorrow, If I sleep to-day,' he may sleep that day;