I was not raised in a religious environment or training focused on any single religion, and I suppose this led me quite early to ponder those questions on my own. That happened primarily in mid-childhood during hikes up into the hills... in the days when children still roamed a little more freely. I concluded at about 9 that for me, God was in nature. I still do sense a sort of spirit in pretty much everything around me and have always been obsessed trying to capture the feeling of fleeting spirits, or maybe just memories of dreams and the sense of spirits from past times disrupting our present day experience.
The focus here is that momentary disruption of your present experience where some sensation triggers your imagination... or the possibility of something else at play. I like to depict this. Sometimes it's the possibility of spirits in nature... the trees, water, air and earth, or spirits that have embodied artwork - ancient paintings, sculpture, reliefs on buildings and bridges. Other times it's the spirits of time past - the sense that spirits past or even our past selves are still with us and can appear, disrupt our sense of stability in fleeting moments and then just as quickly vanish. Then of course there are the spirits we've officially created to substantiate religious beliefs - the gods, devils, angels and the like. I prefer the more obscure ones.