Devarim II - Moshe said it on his own

This is the beginning of the presentation of sources regarding who wrote Devarim. The most important text is the following gemora in Megilla which makes a halachic distinction between Devarim and Vayikra. The Malbim cited offers a solution as to how the whole Torah is Divine i Moshe wrote part of it.

Megila(31b): On fast days the portion of blessings and curses is read and there must not be any break in the reading of the curses. What is source of this rule? R’ Chiya ben Gamda said in the name of R’ Assi said that it is because it says “My son, don’t despise G‑d’s chastisement” – so don’t act as if you don’t want to continue with the reading. Reish Lakish said it is because the beracha on the Torah should not be said on misfortune. So what is the Torah reader to do? A Tanna taught that when the reader starts he should begin the reading with a verse before the curses and when he finishes he should end with a verse after the curses. Abaye said that this rule of not interrupting the reading of the curses only applies to the curses found in Vayikra. However it is permitted to interrupt the reading of the curses found in Devarim. What is the reason for this distinction? Concerning the curses in Vayikra, the Jewish people are addressed in the plural form and Moshe said them at G‑d’s command. In contrast the curses said in Devarim are expressed in the singular form and Moshe said them on his own initiative. Levi bar Buti was once reading the curses in Devarim in a hesitating manner in the presence of R’ Huna. Rav Huna said to him that he could interrupt if he wanted. He explained that the prohibition of interrupting the reading only applied to the curses in Vayikra while it is permitted to interrupt for the curses in Devarim.

Malbim(Devarim 1:3): And it was in the fortieth year – In other words these are matters which Moshe spoke on his own initiative on various occasions in the manner of a preacher who gives chastisement. However he did not have permission to write these words in a sefer and even if he had written them in a sefer they would not have had the sanctity of a Torah scroll. Rather they would be simply considered a collection of his sermons that he said based on his human understanding or as words spoke by a man with ruach hakodesh. However after 40 years G‑d commanded that they be said again to the Jewish people as specific command from G‑d. That is why the verse say, G‑d commanded Moshe to speak to the Jewish people saying.” Similarly G‑d commanded him to writes these words in a sefer at the command of G‑d. Furthermore G‑d said that they should be said and written in a different order than they were originally said in the 11 places but rather in the order that G‑d commanded…. Thus all of Moshe’s words were written by G‑d’s command and he didn’t write them on his own initiative even the point of the smallest letter. Consequently since all the words in Devarim were written at G‑d’s command they have the same halachic status as the rest of the Torah which was written from G‑d’s mouth…