Not only is Jesus running the show in this crazy book, but he has not forgotten his people. Israel is there, front and center, but so is the "vast crowd, too great to count, from every nation and tribe." What are they present to do? Worship. This is why worship in the here and now is so important: it's not just a thing we do as earth-dwellers, but something we will be doing for all eternity. Standing before God, it's really our only logical response.