At the end of each book in his Commentary to the Torah, Ralbag gives us the date he completed it.
At the end of the book of Genesis he tells us that it was completed in October of 1329:
והנה היתה השלמת זה הספר בי"ז יום לירח מרחשון בשנת תשעים לאלף הששי
At the end of the book of Exodus he tells us that it was completed in August of 1330:
ובכאן נשלם הביאור בזה הספר והיתה השלמתו בראש חודש אלול שנת תשעים לפרט האלף הששי
At the end of the book of Numbers he tells us that it was completed in December of 1337:
והיתה השלמתו בכ"ג לחדש טבת של שנת צ"ח לאלף הששי
At the end of the book of Deuteronomy he tells us that the entire Commentary to the Torah was completed in January of 1338:
והיתה השלמתו בכ"ג לירח שבט של שנת צ"ח לפרט האלף הששי
Additionally, at the end of Parshat Bereishit he tells us that the commentary to just that section (which takes up about a third of the entire commentary to the book of Genesis) was completed in August of 1328:
והנה היתה השלמתו בסוף חדש אב משנת השמנים ושמונה לפרט האלף הששי ליצירה
As you might have noticed, I skipped the date of completion for the commentary to the book of Leviticus. This is because he doesn't seem to have mentioned it.
So based on the above we have the following:
- It took him about 14 months to get from Parshat Noach to the end of the book of Genesis.
- It then took him about 10 months to get from there to the end of the book of Exodus.
- It then took him about 7 years and four months to get from there to the end of the book of Numbers.
- It then took him about 1 month to get from there to the end of the book Deuteronomy.
There are also two more bits of information that Ralbag mentions in these concluding statements:
At the end of Parshat Bereishit he says that he wrote it in a very short period of time:
והיתה השלמתו בזמן קצר מאד
Similarly, at the end of the book of Numbers he says that he wrote it in a very short period of time, without access to books, and it therefore requires a second review:
והשלמנוהו בזמן קצר מאד ובזולת ספרים ולזה יצטרך בגזרת ה' לעבור עליו שנית
Thus, we see that the 7+ years between completing Exodus and completing Numbers was not because of Numbers. Which means that the book of Leviticus is what took all that time.
Considering that all the other books took only a short amount of time (ranging from a month to a bit more than a year), why is it that the book of Leviticus took so much longer?
- Is there perhaps something specific about the content of that book that required all those extra years to compose a commentary?
- Do we perhaps know of a particular event during that time period that may have delayed Ralbag?
- Has anyone (Ralbag himself, or later scholars) explained this anomaly, or even noticed it?
Bonus question: Why is Leviticus the only book that does not include the date it was completed, and is this perhaps related to the anomaly of how long it took?