Back to Life
No, we're not talking about the sacred place that boxing, a.k.a. the sweet science, holds in its fans' hearts. And we're not even talking about the fact that you scream "Oh my God! How cute!" when you realize that Rocky's pet turtles are named Cuff and Link.
Rocky is a very religious character, and his faith is apparent from the movie's first shot. The dingy boxing ring isn't particularly holy, but the mural of Jesus over the ring is the first thing you see. And the name of this gym? It's the Resurrection Athletic Center. Fun fact: Resurrection Gym is actually a real location. Stallone revisited it in Rocky V.
Resurrection and Jesus reminds us of Jesus rising, and it casts Rocky as a sort of Christ figure.
He's already been beaten and broken, and this movie is Rocky's resurrection.
Also, a light shines on the ring as Rocky fights. It has a heavenly glow, like some angels left a lamp on. (Who pays the electric bill in heaven?) Or, seen in another light—pun intended—it looks like Rocky has a halo. He's the most ripped and street-smart angel we've ever seen, but we learn that his sweet spirit is pretty dang angelic.
Aside from this opening, the rest of the movie is pretty subtle on the whole religious aspect, apart from Rocky's whole "resurrection" thing. Mr. Balboa has a crucifix beside his bed, and he prays before the big fight. Rocky's religion is explored more in later movies, though.
And, oh yeah: Apollo Creed's name is a riff on the Apostle's Creed, which states:
I believe in God, the Father Almighty,
maker of heaven and earth;
And in Jesus Christ his only Son, our Lord;
who was conceived by the Holy Spirit,
born of the Virgin Mary,
suffered under Pontius Pilate,
was crucified, dead, and buried;
the third day he rose from the dead;
he ascended into heaven,
and sitteth at the right hand of God the Father Almighty;
from thence he shall come to judge the quick and the dead.
I believe in the Holy Spirit,
the holy catholic church,
the communion of saints,
the forgiveness of sins,
the resurrection of the body,
and the life everlasting. Amen. (Source)
Hard to get more religious than that, eh?
Also, check out how the Apostle's Creed makes reference to Jesus "rising from the dead," which echoes the Rocky-as-Christ-figure imagery we see at the beginning of the film. Rocky's career goes from "dead" to pretty spectacularly "alive." A few stints in Resurrection Gym, and our baby Balboa goes from bum to contender for the heavyweight champion of the world.