People often wonder why we sing a cappella, that is, without an instrumental accompaniment. Has anyone every said to you, “But didn’t David play the harp?” He certainly did – God told him to. But God has not told Christians to – so we don’t.
King David is the one who arranged for the use of instruments of music in the temple worship of the Old Testament. The Bible says: “And he set the Levites in the house of the LORD with cymbals, with psalteries, and with harps, according to the commandment of David, and of Gad the king’s seer, and Nathan the prophet: for so was the commandment of the LORD by his prophets.” (2 Chronicles 29:25) So David really did inaugurate the use of musical instruments in temple worship but he did so at God’s command.
Christians, however, have not been authorized to use instruments of music in church worship. We have been instructed to sing and make melody in our heart. The scriptures say: “Singing and making melody in your heart to the Lord.” (Ephesians 5:19; see also Colossians 3:16) Furthermore, the scriptures say that the “sacrifice of praise” that we are to offer to God is “the fruit of our lips.”