Several people who disagree with our contention that instrumental music is unauthorized in the New Testament make the claim that instrumental music is authorized by the command to sing Old Testament psalms.
Since we are commanded to sing psalms in the New Testament (Ephesians 5:19; Colossians 3:16), it follows that we are permitted to practice whatever is sanctioned in the Old Testament psalms! That would include animal sacrifice (Psalm 66:13-15), facing Jerusalem while worshipping (Psalm 138:1-2), worshiping God from the altar in Jerusalem (Psalm 43:3-4), dashing babies against rocks (Psalm 137:2, 4, 8-9), and moving beds and swords into the assembly (Psalm 149:5-6). What proves too much proves nothing!
Furthermore, the instruments listed in the psalms were not optional — they were commanded. It is not enough for someone merely to include just any instrument of their choice. To obey the command of God, they must use the harp, psaltery, trumpet, timbrel, organ, cymbals, etc. To practice, anything taught by Moses but not taught by Christ is fatal, because it places the authority of Moses on par with the authority of Christ (Romans 7:1-4; Galatians 3:13; 4:3, 10; 5:4).
Because the Old Testament has been superseded by the New Testament, authority cannot be found within it for mechanical instruments in our worship!