The religious symbolism here are the wings and how they are usually associated with biblical angels. Considering Gabriel treats Roy like an Angel, even though he directly contradicts this in the story it shows the deception that Gabriel is under and how he treasures his own son very much.

Roy being the only name that isn't religious represents that he kind of strays away from god, especially with his desire to fight at the Rockpile. It is never stated whether Roy goes to these Tarry Services with his family or his father. We never even know if Gabriel himself goes to the service. Roy himself, even though he's the son of a religious man he was born from someone who wasn't exactly christian for most of her life. It is implied that Roy will have to convert himself more into a christian in order to rid himself of dangers that he would encounter, just how he did at the Rockpile.

Roy being also the equivalent to Cain and how Cain killed Abel it can be tied to how Roy, causes the pain and trouble that John goes through with Gabriel. Without Christianity there is an aura of pain caused by Roy.

John: Was the half brother of Roy and not Gabriel's son. John the apostle and John the Baptists in the Bible were known for their faith in Jesus which is shown in the story due to the fact that John was the brother who listened to Gabriel and didn't go to the rockpile. One could argue that Roy is the equivalent to Cain as well. This is expressed by the fact that Cain was the first person to go against God since the "Apple incident". He was also the son of 2 religious parents who have talked with God in the past yet still persists to go against him.

Gabriel: In the bible Gabriel is the Archangel of God and within the story Gabriel is the most religious character who believes that Elizabeth was sinful. This connects the two as they are both the "voice" of God.

Elizabeth: