Charles H. Spurgeon on Psalms 100:2

Serve the LORD with gladness. "Glad homage pay with awful mirth." He is our Lord, and therefore he is to be served; he is our gracious Lord, and therefore to be served with joy. The invitation to worship here given is not a melancholy one, as though adoration were a funeral solemnity, but a cheery gladsome exhortation, as though we were bidden to a marriage feast. Come before his presence with singing. We ought in worship to realise the presence of God, and by an effort of the mind to approach him. This is an act which must to every rightly instructed heart be one of great solemnity, but at the same time it must not be performed in the servility of fear, and therefore we come before him, not with weepings and wailings, but with Psalms and hymns. Singing, as it is a joyful, and at the same time a devout, exercise, should be a constant form of approach to God. The measured, harmonious, hearty utterance of praise by a congregation of really devout persons is not merely decorous but delightful, and is a fit anticipation of the worship of heaven, where praise has absorbed prayer, and become the sole mode of adoration. How a certain society of brethren can find it in their hearts to forbid singing in public worship is a riddle which we cannot solve. We feel inclined to say with Dr. Watts

"Let those refuse to sing

Who never knew our God;

But favourites of the heavenly king

Must speak his praise abroad."