Is it true that one is not allowed to learn Chumash with Rashi at night in preperation for Shabbat? If so why?
The Ari Z’l taught that the night should be devoted to the study of the Oral Torah and that one should not study the “Torah SheBichtav”- the written Torah- at night (Beer Heitev Orach Chayim 238, 2). Chumash with Rashi is however permissible since it has an element of Torah SheB’al Peh (Shut Yabiya Omer 6, Orach Chayim 30). There is no problem with studying Torah SheBichtav even without Rashi on Friday nights (Yabiya Omer).