The brook - The Kidron watercourse, which skirted the city on the east.
Turned back - i. e. he turned westward, and having made the circuit of the city, re-entered by the valley-gate.
Related Commentaries of Nehemiah 2:15
Nehemiah 2:15
15 Then went I up in the night by the brook, and viewed the wall, and turned back, and entered by the gate of the valley, and so returned.