'Commandment' in the Bible

For it was the king's commandment concerning them, that a certain portion should be for the singers, due for every day.

And the chief of the Levites: Hashabiah, Sherebiah, and Jeshua the son of Kadmiel, with their brethren over against them, to praise and to give thanks, according to the commandment of David the man of God, ward over against ward.

And both the singers and the porters kept the ward of their God, and the ward of the purification, according to the commandment of David, and of Solomon his son.