Ephesians 5:19 Speaking to yourselves in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord.
"The reason why singing is such a splendid shield against the fiery darts of the devil is that it greatly helps us to forget him, and he cannot endure being forgotten. He likes us to be occupied with him, with what he is doing (our temptations), with his victories (our falls), with anything but our glorious Lord. So sing. Never be afraid of singing too much. We are much more likely to sing too little.
There are times, however, when we cannot sing aloud. This verse covers that inward singing that so often lifts the heart Heavenward. God make us a singing company."
--Amy Carmichael, in my very favorite devotional of all time, "Edges of His Ways"