"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 (ESV)

When we come together to worship, we do so because of who Jesus is. We are nothing without Him. We have nothing without Him. We deserve nothing from Him. And, yet, He has loved us by giving Himself as a sacrifice for us, so that we who trust in Him would not get what deserve. By His grace we're forgiven. For His glory we're made alive. And so we worship!