Verse 15 By the brook - Kidron. By the gate of the Valley - The valley through which the brook Kidron flowed. It was by this gate he went out; so he went all round the city, and entered by the same gate from which he had gone out.

Neh 2:15

By the brook. "The brook Kidron," which skirted the city on the east. From this he would be able to "look up at the eastern wall" along its whole length, and see its condition. Following the brook, he was brought to the north-eastern angle of the city; on reaching which he seems to have "turned back" towards the point from which he had started, and skirting the northern wall, to have re-entered by the gate of the valley.