John Gill Commentary Nehemiah 13:29

"Remember them, O my God, because they have defiled the priesthood, and the covenant of the priesthood, and of the Levites." — Nehemiah 13:29 (ASV)

Remember them, O my God
The priests, and punish them: because they have defiled the priesthood; by marrying strange wives, and rendering themselves unfit to officiate in it:

and the covenant of the priesthood, and of the Levites ;
made with Levi, Aaron, and Phinehas, see (Numbers 24:11–13) , of the corruption of which, complaint is made, (Malachi 2:4–8) .