How we cite our quotes: All quotations are from Avengers: Age of Ultron.
Quote #1
Ultron: Did you know that this church is at the exact center of the city? The elders decreed it so that everyone could be equally close to God. I like that. The geometry of belief.
This quote nicely mashes together hard science (geometry) with religion (belief), much the way we see a nine-foot robot sitting inside an old church. It's a strange place for Ultron to arrange a meeting, but we're already getting a clue about the way that religion functions for him: as a cultural touchstone that guides his own approach to bringing about the apocalypse. He's thinking along religious lines, specifically the judgy and destructive parts.
Quote #2
Ultron: Upon this rock, I will build my church.
Well this is a strange way to talk about buying vibranium. Nevertheless, Ultron is so stoked about the purchase that he quotes Jesus, who said that same thing to his Apostle Peter in Matthew 16:18. Once again we see Ultron thinking in religious terms, though in this case he sees himself as Jesus. He's definitely copping a holier-than-thou attitude here.
Quote #3
Ultron: Captain America—God's righteous man, pretending you can live without a war.
Not only is Ultron starting to talk about himself like the second coming of Jesus, he's also pointing out the religious hypocrisies in others. It's an interesting thought experiment: would the Avengers still be able to be noble superheroes if they stopped breaking the "Thou Shalt Not Kill" commandment on the regular?