Vayelech recounts the events of Moses’ last day of earthly life. He transfers the leadership to Joshua, and concludes writing the Torah in a scroll which he entrusts to the Levites for safekeeping in the Ark of the Covenant. Vayelech concludes with the prediction that the people of Israel will turn away from their covenant with יהוה, causing Him to hide His face from them, but also with the promise that the words of the Torah would not be forgotten by their descendants.
Deuteronomy 31:1 And Moses went and spoke אֶת־ these words to all Israel. 2 And he said to them, I am 120 years old this day; I cannot go out and come in anymore: and ויהוה said to me, You will not cross over אֶת־ the Jordan this day. C-MATS
Question: Why did Moses say “I am 120 years old this day”? Today my days and years were fulfilled; on this day I was born (Moses’ birthday), and on this day I shall die… This is to teach us that יהוה fulfills the years of the righteous to the day and to the month, as it is written (Exodus 23:26): “אֶת־ the number of your days I will fulfill (You will live out the full span of your lives).” Chumash
Question: What does it mean by “I cannot go out and come in anymore”? Did this mean physically he was too old to go into the Promised Land? Scripture states regarding Moses, “And Moses was 120 years old when he died: his eyes were undimmed and his vigor undiminished.” (Deuteronomy 34:7), which teaches us that his powers were intact even on the day of his passing. So what then is the meaning of “I cannot go out”? Here it means: “I am not permitted,” because authority was taken from him and granted to Joshua. Chumash