These notes are based on the NASB text.

What is the background of Psalm 100?
Although the writer of the Psalm is not identified, he was doubtless a man who had a proper understanding of the person of God. This Psalm is a call to praise and thanksgiving (see the superscription). It was probably sung antiphonally. Verses 1-3 were probably sung by worshipers approaching the temple for worship with verses 4 and 5 serving as the antiphonal response.

Practical Consideration: There are imperatives in our relationship with the Lord.
According to Psalm 100, we are to “Shout joyfully,” “Serve the Lord,” “Come before Him,” “Know,” “Enter,” and “Give thanks to Him [and] bless His name.” These are proper responses of the creature to the Creator.

100:1 Shout joyfully to the Lord, all the earth.

God is worthy of our highest praise and adoration. When a man’s heart has been filled with God’s grace, his countenance and lips should reflect it. The whole earth (all of its inhabitants) is called to praise the Lord.

100:2 Serve the Lord with gladness;
Come before Him with joyful singing.

God is worthy of cheerful service. No one enjoys being served by a moping or depressed servant or waiter who finds his employ a cheerless and irksome task. How often believers do things because they ought to. They pray because it is what they ought to do. They attend worship because it is what they ought to do. They tithe (some of them, anyway) because it is what they ought to do. Believers often do things out of a cold sense of dutiful obligation rather than out of a heart overflowing with gratitude.

God’s people should sing joyfully to Him in worship. Watts, the great hymn writer, penned these words: “Let those refuse to sing who never knew our God; but favorites of the heavenly king must speak His praise abroad.” Lloyd John Ogilvie wrote, “Joy is the outward sign of the inner experience of grace. Gladness, not grimness, is the distinguishing mark of anyone who is truly thankful for the goodness of the Lord.”

Practical Consideration: Our lives should reflect the joy of knowing the Lord.
Christians ought to be the most joyful people on the earth. Our lives should serve as letters of recommendation for knowing God. Our service should be rendered out of a heart filled with gratitude for who God is and what He has done for us. Our worship should be filled with both reverence and joy.

100:3 Know that the Lord Himself is God;
It is He who has made us, and not we ourselves;
We are His people and the sheep of His pasture.

No one assisted God in creation. No one advised Him. He alone is God. He said to Job, “Where were you when I laid the foundation of the earth?” (Job 38:4). Isaiah 55:8-9 records, “‘For My thoughts are not your thoughts, neither are your ways My ways,’ declares the Lord.’For as the heavens are higher than the earth, so are My ways higher than your ways, and My thoughts than your thoughts.'” God has made us. We have not made ourselves nor are we the current product of evolution. Because He made us, we are His. He shepherds us as His people (see also Psalm 23). He knows us intimately and is concerned about us and our needs, even as a shepherd cares for his sheep.

100:4 Enter His gates with thanksgiving,
And His courts with praise.
Give thanks to Him; bless His name.

Gratitude is the theme of this verse. Those who have tasted the goodness of God should give thanks. Those who have been forgiven should give thanks. Those who understand who God is and what they are in relation to Him should give thanks.

100:5 For the Lord is good;
His lovingkindness is everlasting,
And His faithfulness to all generations.

The statement, “For the Lord is good,” sums up God’s character and is more than sufficient reason for us to praise Him. He indeed is good. Someone has rightly stated that God does not use us because we are good, but because He is good. We should praise Him because He is good and merciful and absolutely trustworthy.

Practical Consideration: We should praise God because of who He is.
We should praise God because of who He is. He alone is God. He is good. He is merciful. Mercy is an expression of His goodness in relation to sinners. He is faithful. He is just and right in all His dealings with man and always keeps His word.