Bede

And they rebuilt the old gate, etc. That old gate is what John mentions, saying: Beloved, I do not write a new commandment to you, but an old commandment which you have had from the beginning (1 John 2). The old commandment is the word which you have heard. Therefore, the old gate is rebuilt in Jerusalem, when the word of faith and love, which has been handed down from the beginning of the holy Church, is either recovered in those who have gone astray, or begins to be established in those recently believing.

Commentary on Ezra and Nehemiah ↗