What does Nehemiah 13:19 mean?

So as soon as it started getting dark at the city gates before the Sabbath, I ordered the doors to be shut and told them not to open them until the Sabbath was over. I also put some of my own men at the gates to make sure no one brought in any loads on the Sabbath day. Nehemiah 13:19 - Modern Text Bible

(Nehemiah takes practical steps to protect the Sabbath, making sure no business happens during the holy day by closing the gates and posting guards.)