Before the Exile
About guarding the city walls on the Sabbath in ancient Israel, the Bible has a clear passage that shows that the gates of the wall were closed before the Sabbath. And consequently, there were no guards placed at the city walls.
After the Exile
After the exile, and for a temporary period, guarding the city wall became necessary. So, guards were placed not to protect the wall but to enforce the law of keeping the gates closed and stop all work transactions from taking place on the Sabbath. This is seen in the following passage:
“So it was, at the gates of Jerusalem, as it began to be dark before the Sabbath, that I commanded the gates to be shut, and charged that they must not be opened till after the Sabbath. Then I posted some of my servants at the gates, so that no burdens would be brought in on the Sabbath day. Now the merchants and sellers of all kinds of wares lodged outside Jerusalem once or twice.”
“Then I warned them, and said to them, “Why do you spend the night around the wall? If you do so again, I will lay hands on you!” From that time on they came no more on the Sabbath. And I commanded the Levites that they should cleanse themselves, and that they should go and guard the gates, to sanctify the Sabbath day” (Nehemiah 13:19-22). Nehemiah assigned his own servants the job of guarding the gates (verse 19) on the Sabbath so people will not desecrate it.
This charge was committed to the Levites, whom Nehemiah had recently brought back to the city (Nehemiah 13:11). This duty had been given to them when the gates were first set up (Nehemiah 7:1), but had been ignored when the Levites, who lacked financial support, had left their jobs in Jerusalem to provide for their families through farming. After having worked for some time in secular work, the Levites had to cleanse themselves before again performing their holy duties.
In His service,