"Araby" is a story about infatuation, and these particular sentences reflect that theme of infatuation. It is part of a larger paragraph, which details the strength of this emotional pull by which Mangan's sister exerts an ever-present hold over the young narrator's heart. It is all-consuming, following him everywhere, holding control of his imagination, and yet, at the same time, the young narrator treats it with a religious kind of awe (keep in mind, the sacral language in this passage, via the chalice, as well as prayers). There's a tension running throughout this paragraph, between life's banalities on the one hand, which runs against this emotional intensity on the other. In this longer passage, I'd suggest that Joyce's narrator is reflecting the intensity of his own feelings, along with the degree to which he cherishes that infatuation, with a religious kind of fervor.