There are a number of words or phrases in "Araby" that refer to religion. The opening line refers to "Christian Brothers' School" setting the boys free. The second paragraph opens with "The former tenant of our house, a priest, had died in the back drawing-room" and mentions religious books and spiritual qualities.
In addition to explicit references like these, there are phrases that are often associated with religious practice, such as mentioning "chanting," senses being "veiled," and so on. Fairly early in the story the narrator says, "pressed the palms of my hands together until they trembled, murmuring: "O love! O love!" many times." This sounds very much like he's putting his hands together in prayer.
Since the school is mentioned as a place of captivity, and the priest is mentioned as being dead, I'd say these references suggest a world where formal religion is dead or can't address the needs of the people, but also a world where religious sensation and impulses are very much alive and turned to secular purposes. It is as if the narrator sees himself as a figure from religious myths, and treats Mangan's sister like she's the Virgin Mary.