There are many themes present in Andrew Lloyd Webber's rock opera, Jesus Christ Superstar. First there is the theme that self-sacrifice for the good of humanity is to be admired and is clearly a higher calling. This is demonstrated when Jesus willingly dies for those who have shunned and beaten him. Also, the theme of the importance of loyalty to one's friends is highlighted when Judas sells the whereabouts of Jesus to the high priests for 30 pieces of silver. As a result of this betrayal, Judas feels remorse at the end and hangs himself. Another theme that is suggested is that love triumphs evil. Clearly, Jesus's sacrifice showed his followers the importance of agape - doing what is right by others even when you don't want to.
The above answer clearly delineates the values and "themes" of Christianity as told through the New Testament, but the musical has "themes" of its own, too: The metaphysical comparison to rock stars, "superstars," point to the theme of the "ego trip" of having "followers" and how dangerous this inflation can be to the original goal of the "superstar." Another theme explored in the musical is the inevitability of the events running their course, with such characters as Mary Magdalene and Judas contributing to the forward motion of events. On the highest level, the musical dramatizes the social momentum that builds up around extraordinary persons; by treating the coming of Christ not as a religious event, but as a social phenomenon, the authors are dramatizing Jesus' humanity, God made man. This includes his physical relation with Mary or with John, and his very human hesitation at "fulfilling" his destiny. "I Don't Know How to Love Him" is an anthem for all humanists.