"Make a joyful noise to the Lord, all the earth!
Serve the Lord with gladness!
Come into his presence with singing!
Know that the Lord, he is God!
It is he who made us, and we are his;
we are his people, and the sheep of his pasture.
Enter his gates with thanksgiving,
and his courts with praise!
Give thanks to him; bless his name!
For the Lord is good;
his steadfast love endures forever,
and his faithfulness to all generations" (Psalm 100:1-5)
"It is a throne of grace that God in Christ is represented to us upon; but yet it is a throne still whereon majesty and glory do reside, and God is always to be considered by us as on a throne." – John Owen
Man, due to his deformed nature, tends to worldliness and carnality, so much so that even the redeemed must be called by God to worship Him in a way that is acceptable and pleasing to Him. Thus the reading of Scripture, such as the Psalm above, serves to call God's people to Reformed, Biblical worship. It is no accident that those churches which stray away from Reformed worship tend to be man-pleasers in their worship, even to the point of using entertainment as a church growth gimmick, never considering that worship belongs to God, and He alone has the right to determine how he is to be worshiped.
When one considers that God, the Sovereign Creator of the Universe, has called us into His presence, a certain awe and reverence is bound to overtake us. When sinful man stands in the presence of a righteous and omnipotent God, what else may be our response other than "Woe is me, for I am undone". (Isaiah 6:5). In such a presence, there is no room for jugglers, clowns, silly skits, rock concerts, or whatever other irreverent items that are included in modern "worship". For the God who demands our worship tells us that we may not do these things (Deut. 12:32).
Needless to say, much of what is done today in the "presence of the Lord" has little to do with God's presence. Many churches have reduced their worship to mere "celebration" services, never giving thought to their own sinfulness or to God's holiness. While the Christian should rejoice at his redemption, he must be mindful of the fact that God's throne of grace is still a throne, and an almighty and sovereign Judge sits upon that throne.
"You must never come into God’s presence but as a poor worm, and if there is any difference that is made between you and others in outward respects, it is nothing to you. When you are in the presence of God, you are as a base, vile worm though you are a prince or an emperor." (Jeremiah Burroughs - Gospel Worship, Soli Deo Gloria, p. 137)
The call to worship, being God's call, is not merely an invitation, but an authoritative commandment. The call is a universal call, going out to all people every sabbath, and there is no excuse for not heeding the call. The beauty of God's call to worship is that He calls us, as he did Adam and Eve, despite or fear and unworthiness. May we give attention to the importance of God's call to worship Him, and do so with reverence and awe.
Recommended Reading: With Reverence and Awe: Returning to the Basics of Reformed Worship by Hart and Muether