During the three days in Jerusalem, Nehemiah with the utmost tact, planning, and wisdom surveyed the walls of Jerusalem. He may have been ruminating on many questions and problems: how to obtain the support of the people, how to go about rebuilding the wall, how the resources had to be used, how to deal with potential obstacles, etc. Instead of resting or socializing with the people, the text implies he went right to work—at night.
Rather than receiving information from second-hand sources, descriptions from others’ perspectives, and depending on rumors and opinions, Nehemiah went out and looked at the condition of the problem with his own eyes. He asked questions of himself and answered them for himself conclusively.
Remarkably, Nehemiah did not tell anyone about his night watches. Nehemiah 2:12 and 16 emphasize this point. The first verse underscores that no one knew, not even any of the animals, except the one he rode on. The second verse lists the people who did not know what he was doing: the Jews, priests, nobles, officials, or others.
Possibly the honor of God and the welfare of Jerusalem worried him so much that he could not sleep. Perhaps he desired to keep his observations and conclusions to himself until the time was appropriate to share them. Regardless, it is clear that his intentions were not publicized and this wise act prevented enemies from knowing what was going on.
In the emphatic context of Nehemiah being alone, verse 12 does also state that a “few men” were with him. Although he was discrete and kept his information confidential, apparently Nehemiah did keep a couple of trusted assistants with him.