Nehemiah 11:23
For it was the king’s commandment concerning them, that a certain portion should be for the singers, due for every day. For it was the king’s commandment concerning them, that a certain portion should be for the singers, due for every day.
Nehemiah 11:23 belongs with the historical material in Ezra and Nehemiah, such as the lists of names found there. It is not a promise but simply records a historical detail. That detail is the king's commandment that a certain daily due portion should be provided for the singers.