Romeo and Juliet use some religious metaphors, both in the balcony scene and when they first meet, to signify just how all consuming their love, or infatuation, has become. Their infatuation has become so all consuming that it has even replaced their religious and spiritual beliefs.
One religious metaphor we see in the balcony scene, Act 2, Scene 2, is when Romeo compares Juliet to an angle, as we see in his lines:
O, speak again, bright angel! for thou art
As glorious to this night, being o'er my head,
As is a winged messenger of heaven. (II.ii.28-30)
It is Romeo's physical attraction for Juliet that makes him see her as a celestial being. In seeing her as a celestial being, he is glorifying her, making her seem more magnificent than she really is. In addition, because he is glorifying her, Juliet has become his religion. Therefore, the religious metaphor shows us that his love for her is so all consuming that it has even replaced his religion.
Even Juliet shows us that her infatuation for Romeo has replaced her religion when she refers to Romeo as "the god of my idolatry" (119). Idolatry is the worship of physical objects as gods themselves rather than worshiping the Judeo-Christian God. As a Catholic, Juliet would have known idolatry to be one of the gravest sins and one forbidden in the ten commandments. Therefore, her confession that she is worshiping Romeo for his physical appearance shows that Juliet has also let her infatuation with Romeo replace her religious beliefs.