Here are two paragraphs from Liz Moore’s God of the Woods:
She saw everything. She sat on the edge of the stage that overlooked the community room, watching her campers in all of their triumphs and failures, the ones having genuine fun, the ones pretending to have it.
If she believed in a God, it was in one who functioned something like Louise in this moment: rooting for her charges from afar, mourning alongside them when they were rejected, celebrating every small victory that came their way. She noticed the lonely ones, the ones at the edge of the crowd; she felt in her heart a sort of wild affection for them, wanted to go to them, to stand next to them and pull them tightly to her side; and yet she also knew that to intervene in this way would disrupt something sacred that—at twelve and thirteen and fourteen years old—they were learning about themselves and the world. And this, too, was how she thought of God.
Consider characterization by thoughts about the divine. Characters might not believe at all or might not believe as aggressively and fervently as the most devout evangelists or believe to various changing degrees. What characters consider divine (their money, spouse, time with their phone or family, God) reveals them to readers as well. Does what characters consider divine put them at odds with some of the other characters around them? Does it make them a member of a community or organization? How do they feel about that membership? How do people important to them feel about it? If you’re writing literary realism, is there a faith tradition you want to mention specifically? If you’re writing fantasy, do you need to invent a pantheon? How might meeting aliens change your characters ideas about all of this? What other life events might strengthen or weaken a character’s resolve, whatever their position?
Moore’s paragraphs above quickly show readers Louise’s view of the world, other characters in it, the setting, and a bit about her view of herself. That kind of quick characterization is valuable for writers.