Why is it that many of the most devout Christians constantly reassure themselves of their faith, that they know it’s true, that they know everything is in God’s or Jesus’s loving hands?
Muslims do much the same, as do some Hindus in the US. (Adjusting for cultural and religious differences.)
Can you imagine the same concerning something that can be demonstrated as being true?
Gravity loves me, this I know!
Newton’s apple tells me so.
Praise Gravity every day
So our stuff won’t float away.
No, of course not.
Likewise for constant assertions that “My faith in God is at the center of everything I do.” “Every decision I make, I ask myself what is the best way to honor God.”
Can you imagine the same concerning other fundamental aspects of your being? “First and foremost I am a eukaryote. Don’t ask me to do anything without keeping that in mind.”
My proposed explanation: The devout know deep down that their religion isn’t really true. They can’t accept this, so they aver their faith ever louder to drown out their doubts.
There may be some elements of cosmological truth if you close one eye and squint with the other, but the explanations of the world invented by Bronze Age nomads do not suit the modern world at all. The holy works of various religions may contain useful advice for living your life and for living with other people. There’s a lot of bad advice in there, too, so at best that’s a wash if you’re trying to live your life strictly in accordance with your religion.