Christianity is a motif that Kinney weaves through Greg’s narrative. It represents comfort, hope, strength, and patience. It is something he refers to regularly while considering his life or the circumstances that create a series of events. While staying in his grandmother’s basement with his family, Greg feels isolated and stir-crazy, and he knows the rest of his family does too. He thinks about a children’s book that Manny has, which tells the story of Noah’s Ark, and Greg relates this to his own life: “Whenever I feel sorry for myself living in Gramma’s basement with my family, I think about Noah and it makes me feel a little better” (12). He is inspired by Noah’s patience and strength and tries to embody those characteristics. Biblical examples are a rare time in the book (and series) when Greg gains personal insight and grows in maturity. The early reference to Noah prefigures the natural disaster at the book’s climax and the narrative lesson on resilience, family, and providence, which is at the heart of the story.

The book’s treatment of Christianity is often humorous. Greg notes his belief that “God has a sense of humor” (184), and the story often uses Christianity as a way to satirize Greg’s worldview as a young boy.