Go out and come in, i.e. perform the office of a leader or governor, either because I now find a decay of my mind and body, which seems not well to agree with Deuteronomy 34:7, or because I foresee the time of my death approaches.
Related Commentaries of Deuteronomy 31:2
Deuteronomy 31:2
2 And he said unto them, I am an hundred and twenty years old this day; I can no more go out and come in: also the LORD hath said unto me, Thou shalt not go over this Jordan.