Albert Barnes Commentary Nehemiah 12:31

"Then I brought up the princes of Judah upon the wall, and appointed two great companies that gave thanks and went in procession; [whereof one went] on the right hand upon the wall toward the dung gate:" — Nehemiah 12:31 (ASV)

I brought up - Note the resumption of the first person, which has been laid aside since (Nehemiah 7:5), and which is confirmed now to the end of the book. It is generally allowed that we have here once more a memoir by Nehemiah himself.

The two “companies” or choirs, having ascended the wall on its western face, near the modern Jaffa Gate, stood looking eastward toward the city and temple; then the southern choir, being on the right, commenced the circuit of the southern wall, while the choir on the left proceeded around the northern wall (Nehemiah 12:38–39), until both met on the eastern wall, between the water and the prison gates.