Nehemiah 13:1

On that day
Not when the wall of the city was dedicated, nor quickly after; for it cannot be thought that people should be so corrupted so soon as this chapter shows; but when Nehemiah had governed them twelve years, and had been at Babylon, and was returned again, as appears from ( Nehemiah 13:6 ) , compared with ( Nehemiah 2:1 Nehemiah 2:6 ) ( 7:2 ) ,

they read in the book of Moses in the audience of the people;
for from the time of the reading of the law by Ezra, ( Nehemiah 8:1 ) it became a custom to read the law publicly:

and therein was found written, that the Ammonite and the Moabite should
not come into the congregation of the Lord;
that is, be admitted to marry with any of the people of Israel; (See Gill on Deuteronomy 23:3).