Verse 1-2
Psalms 100:1-2. Make a joyful noise unto the Lord — Partly, with voices, and songs of rejoicings, and thanksgiving; and partly with musical instruments, as the manner then was; all ye lands — That is, all the inhabitants of the earth. When all nations shall be discipled, and the gospel preached to every creature, then this summons will be fully obeyed. Serve the Lord with gladness — Devote yourselves to, and employ yourselves in, his service. Come before his presence with singing — In the ordinances which he has appointed, and in which he has promised to manifest himself to his people. In all acts of religious worship, whether in secret or in our families, we may be truly said to come into God’s presence; but it is in public worship especially that we enter into his gates, and into his courts, as expressed Psalms 100:4, which should be with thanksgiving for so great a privilege, and with praise for his goodness manifested herein.

Verses 3-5
Psalms 100:3-5. Know that the Lord — Hebrews Jehovah, he is God — The only living and true God; a being infinitely perfect, self-existent, and self- sufficient; and the fountain of all being; the first cause and last end of all things. It is he that hath made us — Not only by creation, but by regeneration, which is also called a creation, because by it we are made his people. Hence we owe him homage and service, and him only. and not other gods, who did neither make nor new-make us. He, and he only, hath an incontestable right to, and in us, and all things. His we are, to be influenced by his power, disposed of by his will, and devoted to his honour and glory. We are his people — Or subjects, and he is our prince or governor that gives law to us, as moral agents, and will call us to an account for what we do; the sheep of his pasture — Or, as the Hebrew may be rendered, the flock of his feeding, whom he takes care of and provides for. He that made us, maintains us, and gives us all things richly to enjoy. For the Lord is good — Infinite in goodness, and therefore doeth good. His mercy is everlasting — Is a fountain that can never be drawn dry. His truth endureth to all generations — And no word of his shall fall to the ground as antiquated or revoked: his promises are sure to all the faithful, from age to age. If this Psalm be considered as prophetical of the calling both of Jews and Gentiles to the profession of the gospel, then by the gates of Zion, Psalms 100:4, must be mystically understood the Christian Church.