1. Why does the Gemara bring a proof from Zevulun ben Dan if it ultimately doesn't answer the questions a) son vs. grandson and b) the Gemara brings a proof that only mikra is required?
2. How does veshinantom imply veshilashtom?
3. Why does the Gemara not bring the middle word of Tehilim-is it possibly because of the question of halleluka being one or two words?
4. Why so many proofs for al tegamgem-ve'omer, ve'omer, etc.?
Thank you for your wonderful work.
Gershon Dubin, Brooklyn, NY, USA
1. Initially, we cited Zevulun ben Dan as proof that a father is obligated to learn with his son all the things that he learned with his grandson. The Gemara refutes this proof from a Beraisa. If that was the end of the story, your question would hardly be justified, since the initial proof was genuine.
Rashi, however, goes one stage further. He explains that the Gemara's proof from Zevulun ben Dan is upheld, since the question was not what one is obligated to learn with one's son (which we already know from the Beraisa), but how far down the line one is obligated to learn with one's descendants. The proof from Zevulun ben Dan is that one need only learn as far down as one's grandson, and no further.
Do you still have a problem?
2. Rashi (see Rashi in the Rif and the Maharsha) explains that had the Torah wanted to instruct us to learn sharply (or that one should review it once) it would have written "ve'Shinisem" (with one "Nun"). Now that it writes "v'Shinantam," with two "Nunin," it is coming to teach us to learn it again and then to learn it a third time.
The Maharsha adds that "Al Tikri v'Shinantam ..." is based on the principle that the five letters of 'Datelnat' are interchangeable, allowing us to change the 'Nun' for a 'Lamed'. I assume that this explanation only works in conjunction with that of Rashi, since without it, 've'Shilaltam' doesn't work.
3. The Etz Yosef explains that the Gemara cannot give us the middle word of Tehilim because of the She'eilah in Pesachim as to whether "Halelukah" (plus a few other words, ending in 'Kah') is one word or two - just as you suggested.
4. Although the Maharsha does not actually ask your question, he seems to answer it by inserting a Chidush with regard to each proof:
The second Pasuk ("Kashram al Etzbe'osecha"), he says, comes to teach us that one's knowledge should be so clear that one is able to converse with sign language alone without even speaking.
The third Pasuk ("k'Chitzim b'Yad Gibor ... ") adds that one's major success in learning comes in one's youth.
The subsequent Pesukim teach us the praiseworthiness of learning with as many Talmidim as possible when they are young.
Be'Virchas Kol Tuv,
Eliezer Chrysler