Deuteronómio 31:2 Comentario: Rashi, Chizkuni, Da'at Zekenim & Ramban

וילך משה וגו' ... אנכי היום AND MOSES WENT ... I AM [HUNDRED AND TWENTY YEARS OLD] THIS DAY — Today my days and my years become full: for on this day (the seventh of Adar; cf. Rashi on Deuteronomy 1:3) I was born and on this day I must die (Sotah 13b).

אמר אלי לא תעבור את הירדן הזה, “He had said to me: you will not cross this river Jordan.” You, the people, will not lose anything by that fact, as G-d Himself will cross the river Jordan ahead of you, leading you. (verse 3)

בן מאה ועשרים שנה אנכי היום לא אוכל עוד לצאת ולבא, “I am one hundred and twenty years old today, I can no longer go out and return home.” One reason I cannot do so is my age; another reason is the fact that G–d has forbidden me to cross the river Jordan. You will not suffer a setback by my not crossing the Jordan, as G–d, personally, will cross with you, and He will destroy etc.;” i.e. כי ה' הוא עובר לפניך והוא ישמיד וגו'. I do not feel weak, but I must obey G–d’s command.

לא אוכל עוד לצאת ולבוא I CAN NO LONGER GO OUT AND COME IN — One might think that this was because his physical strength failed him! Scripture, however, states (Deuteronomy 34:7) “His eye was not dim nor his natural force abated!” What then is the meaning of לא אוכל? It means: “I am not permitted” (cf. Rashi on Deuteronomy 12:17 and Deuteronomy 24:4), because the power (leadership) is being taken from me and given to Joshua. — Another explanation of לצאת ולבוא is: I can no more take the lead in the matter of the Law; this teaches us that the traditions and the well-springs of wisdom were stopped up for him (cf. Sotah 13b).