An Obviously Stated Epigraph

Chapter 9 brings to the reader the epigraph of the novel. Vonnegut very explicitly points out "the epigraph of this book is the quatrain from the famous Christmas Carol...
The cattle are lowing,
The Baby awakes.
But the little Lord Jesus
No crying he makes" (197).
Vonnegut nicely tells the reader this quatrain is the epigraph, and doesn't leave it to be questioned. This epigraph makes sense though as Billy endured many tough and gruesome times but he hardly cried. Billy like Jesus when he is awoken doesn't cry but remains at peace and tries to carry on.