John Gill

Serve the Lord with gladness,.... Not with a slavish fear, under a spirit of bondage, as the Jews under the legal dispensation; not in the oldness of the letter, but in the newness of the Spirit: with spiritual joy and freedom of soul, as under the spirit of adoption; readily, willingly, cheerfully; without sinister and selfish ends and views; as their Lord and Master; taking delight in his person, and pleasure in his service; rejoicing in him, without having any confidence in the flesh: come before his presence with singing; to the throne of his grace with thankfulness for mercies received, as well as to implore others; and into his house, and at his ordinances, beginning public worship with singing psalms, hymns, and spiritual songs; see Psa 95:2.