Rav Yehoshua bar Abba quotes Rav Giddel in the name of Rav, as teaching that the last eight pesukim of theTorah have a unique status – that “an individual reads them in the synagogue” – that they are a unique single unit. What is special about these last eight pesukim?
Rabbi Yehuda says that Moshe could not possibly have written the last eight pesukim of the Torah, which open with the words “So Moshe the servant of the Lord died there in the land of Moab” ( 34:5). How could Moshe be alive and writing that he had died!? Therefore he concludes that Yehoshua completed the last few verses of the Torah.
Rabbi Shimon rejects the possibility that the Torah was not completed by Moshe in its entirety, since the Torah describes Moshe handing the complete book to the children of Levi (see 31:26). The picture that he paints of the writing of the Torah, is Moshe writing according to the instructions of God, and beginning with the last eight pesukim, God told Moshe what to write, and Moshe wrote according to those instructions be-dema.
This term, be-dema – apparently a reference to tears – is the subject of discussion among the rishonim and aḥaronim.
The Ritva suggests that due to his sadness, Moshe was unable to repeat these passages as he wrote them, and he wrote them while crying. According to this approach, God who is omniscient instructed Moshe to write about a future event, and there is no issue with Moshe’s inability to write that he died while he was still alive.
The Ramah’s reading of the baraita was that the rest of the Torah was written by Moshe in ink, and the last pesukim were written with his tears, i.e. pseudo-writing that was preparation for Yehoshua to fill in with ink.
The Maharal writes that Moshe’s crying is indicative of the beginning of his death, as decreed by the word of God. Thus once the statement was made by God, Moshe could reasonably write that he was, in fact, dead.
A final interpretation, which is brought in the name of both the Gr”a and the Ba’al Shem Tov, rests on the understanding of dema as “a mixture.” This approach suggests that the entire Torah was a collection of letters that ordered themselves meaningfully as events took place. Moshe wrote these last pesukim as a collection of jumbled letters, which ordered themselves and became meaningful after his passing.