Christianity

In chapter 3, we have three refrences to christianity. First, in the beginning of the chapter, Billy sees Adam and Eve in the golden reflection of the German corporal's boots. He refers to them being "so innocent, so vulnerable, so eager to behave decently" (53). I think that this shows much of Billy's own innoncence, and the way he thinks. He views their innocent beings as beautiful, and loves them for it. However, when he 'time travels' or imagines being in 1967, a prayer on Billy's wall displays the prayer "God grant me the serenity to accept things I cannot change, courage to change the things I can, and wisdom always to tell the difference" (60). The author then states that although this was his encouragement that kept him going, he was unenthusiastic about living. This statement confused me. If he used this prayer to encourage him, then why is he unhappy with living? Is it maybe hinting that Billy is trying to change things he cannot change, and doesn't have the wisdom to know the difference between the changeable, and unchangeable? However this thought is erased by the next sentence which states "among the things Billy Pilgrim could not change were the past, the present, and the future" (60). Perhaps this is why he is so unenthusiastic about living, because he has no hope for what lies ahead of him.
The third reference to christianity, or religion, is when Billy Pilgrim is back in World War II, on the train as it slowly started to head eastward. The author says that "somewhere in there was Christmas" (71). Billy does not seem to feel anything about it being Christmas day. He did not seem to feel sad or lonely about being unable to celebrate Christmas. Infact, he does not even seem to recognize it being Christmas day at all.