Christian worship is our corporate and private response to God.  It expresses glory to God as we recognize the atoning work of Christ and the power of His Holy Spirit.  

As the Psalmist has written:  

Psalm 150

1 Praise the Lord!
Praise God in his sanctuary;
    praise him in his mighty heavens!
2 Praise him for his mighty deeds;
    praise him according to his excellent greatness!

3 Praise him with trumpet sound;
    praise him with lute and harp!
4 Praise him with tambourine and dance;
    praise him with strings and pipe!
5 Praise him with sounding cymbals;
    praise him with loud clashing cymbals!
6 Let everything that has breath praise the Lord!
Praise the Lord!