True praise is heart work. Like smoking incense, it rises from the glowing coals of devout affection. Essentially, it is not a thing of sound: sound is associated with it very properly for most weighty reasons, but still the essence and life of praise lie not in the voice, but in the soul. Your business in the congregation is to give to spiritual praise a suitable embodiment in harmonious notes. Take care that you do not depress what you should labour to express. Select a tune in accordance with the spirit of the psalm or hymn, and make your style of singing suitable to the words before you. Flippantly to lead all tunes to the same time, tone, and emphasis, is an abomination; and to pick tunes at random is little less than criminal. You mock God and injure the devotions of His people if you carelessly offer to the Lord that which has cost you no thought, no care, no exercise of judgment. You can help the pious heart to wing its way to heaven upon a well-selected harmony; and you can, on the other hand, vex the godly ear by inappropriate or unmelodious airs, adapted rather to distract and dishearten, than to encourage intelligent praise.
—Charles Haddon Spurgeon. The Sword and The Trowel, June 1, 1870, 276-277