Speak to one another with psalms, hymns and spiritual songs. Sing and make music in your heart to the Lord... - Eph 5:19
As a result of the distinctive plea of the church - a return to New Testament Faith and practice - acappella singing is the only music used in the worship. This singing, unaccompanied by mechanical instruments of music, conforms to the music used in the apostolic church and for several centuries thereafter (Ephesians 5:19). It is felt that there is no authority for engaging in acts of worship not found in the New Testament. This principle eliminates the use of instrumental music, along with the use of candles, incense, and other similar elements.