Its gates shall never be shut by day: this says only that the gates stay open all day long. But in light of what follows, and there shall be no night there, it is clear that the text means the gates will stay open all the time, twenty-four hours a day (see Isa 60.11), because in the new Jerusalem there will be no nighttime, when city gates are closed. There will be light a full twenty-four hours every day.

Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on The Revelation to John. (UBS Handbook Series). New York: UBS, 1993. For this and other handbooks for translators see here .