What about instruments? Surely, Psalm 150, alone, should have definitive bearing on this question. The arguments against them say that, in the temple worship in Israel, musical instruments were used only when the sacrifices were being offered. Today, since the sacrifices of Israel have been abolished by the completed sacrifice of Jesus on the cross, the music that was associated with the ancient sacrifices should be abolished, too. That is, certainly, special and (I would say) unpersuasive pleading. Were instruments really used only when sacrifices were offered? How could we possibly know? What about this psalm? It tells us to praise God with a variety of instruments and says nothing about sacrifices. What about the worship of God in heaven, according to Revelation? There are harps in heaven (Revelation 5.8) and trumpets (Revelation 8.6-8, 10, 12; 9.1, 13). There is singing, all of it in words not found explicitly in Psalms. How can we deny that Psalm 150 endorses the use of new songs and instruments in worship?
From: Psalms: An Expositional Commentary: Volume 3: Psalms 107-150 by James Montgomery Boice (Grand Rapids: Baker Books, 1998), pp. 1,289-1,290. An excerpt from: “Everybody, Praise the Lord” (a sermon on Psalm 150).