How can the timing of the Torah's revelation mentioned in the Hadith—"The Torah was revealed on the sixth of Ramadan"—be reconciled with what the Qur’an in Surat Al-A'raf, verses 142-145, states regarding Moses’ appointment with his Lord for thirty nights, which he completed with ten, and which Ibn Abbas interpreted as being in Dhu al-Hijjah?

The Hadith (definition) that specifies the dates of the revelation of the heavenly books in Ramadan (definition) (the scriptures of Abraham on the first night, the Torah after six days, the Gospel after thirteen, and the Criterion after twenty-four) has a weak chain of narration.

There is another narration from Qatadah, from his companion, from Abu al-Jald, which specifies different dates for the revelation of the books (the scriptures of Abraham on the first night, the Torah after six days, the Psalms after twelve, the Gospel after eighteen, and the Qur'an after twenty-four). This chain of narration is sound, but it is mawquf (stopped at a Companion or Successor).

Al-Bayhaqi also narrated a Hadith from 'Imran with the same first chain of narration, then mentioned that Ibrahim ibn Tahman narrated it from Qatadah as his own statement.

Therefore, the marfu' (elevated) Hadith is weak and cannot be used as evidence. As for the athar (narration) that is mawquf on the Successors, it also cannot be used as evidence.

Regarding the Torah and the Tablets: The Qur'an mentions that Allah promised Moses thirty nights and completed them with ten, and wrote for him on the tablets an admonition for everything and a detailed explanation. Commentators have differed on whether these tablets are the Torah or something else. The correct view is that the tablets are distinct from the Torah.

In summary: The heavenly books that Allah revealed to His messengers generally are: the scriptures of Abraham and Moses, the Torah, the Gospel, the Psalms, and the Qur'an. The scriptures are distinct from the books, for Moses received the scriptures and tablets before the Torah.