So, I've noticed in a lot of Green Day's music they mention/reference religion. This can be seen in American Idiot with songs like "St. Jimmy" and "Jesus of Suburbia," being some of the obvious ones.
In 21st Century Breakdown, almost every song mentions religion in the form of saints, Christians, and religious figures.
In an interview with Bill Maher (I know he's not in the best standing, but the interview is still a good one) right after the release of 21CB Billie talks about religion and how his mother's religious views impacted his life and songwriting. Here's the link:
Enjoy! Please let me know what you think.