'Commandment' in the Bible

For it was the king's commandment concerning them, and there was a settled portion for the singers, due for each day.

And the chief 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, with the singers and the doorkeepers, they kept the ward of their God, and the ward of the purification, according to the commandment of David and of Solomon his son.