A classic from the Prince of Preachers:
The Reason for Singing
The Lord thy God in the midst of thee is mighty; he will save, he will rejoice over thee with joy; he will rest in his love, he will joy over thee with singing. (Zephaniah 3:17)
What a word is this! Jehovah God in the center of His people in all the majesty of His power! This presence alone suffices to inspire us with peace and hope. Treasures of boundless might are stored in our Jehovah, and He dwells in His church; therefore may His people shout for joy.
We not only have His presence, but He is engaged upon His choice work of salvation. “He will save.” He is always saving: He takes His name of Jesus from it. Let us not fear any danger, for He is mighty to save.
Nor is this all. He abides evermore the same, He saves, He finds rest in loving, He will not cease to love. His love gives Him joy. He even finds a theme for song in His beloved. This is exceedingly wonderful. When God wrought creation He did not sing but simply said, “It is very good”; but when He came to redemption, then the sacred Trinity felt a joy to be expressed in song. Think of it, and be astonished! Jehovah Jesus sings a marriage song over His chosen bride. She is to Him His love, His joy, His rest, His song. O Lord Jesus, by Thine immeasurable love to us teach us to love Thee, to rejoice in Thee, and to sing unto Thee our life-psalm. – C.H. Spurgeon