and the elders fell down and worshiped...

Why?

"Worthy are you, our Lord and God, to receive glory and honor and power, for you created all things, and by your will they existed and were created." Revelation 4:11

"Worthy are you to take the scroll and to open its seals, for you were slain, and by your blood you ransomed people for God from every tribe and language and people and nation, and you have made them a kingdom and priests to our God, and they shall reign on the earth." Revelation 5:9-10

"Worthy is the Lamb who was slain, to receive power and wealth and wisdom and might and honor and glory and blessing!" Revelation 5:12