Sam wasn't new to religion. Because of the horrific things he'd see as a hunter, it was at least helpful to believe in the little good left of the world. It gave him hope in what was to come for him after death. And because of his developing faith, it was becoming a reoccurring event where the youngest Winchester would pray himself to sleep after every hunt.
He definitely needed it now. Lost souls, innocent lives, blood spilled on his hands. A certain horror was gnawing at his brain, and he needed to get it out the best (and safest) way he knew how: praying. The second his exhausted form tossed itself onto the motel bed, sore muscles finally easing themselves against the mattress, he muttered out a prayer. It didn't matter to who or what he was praying to, he just needed to let out the cry for help. For forgiveness. And just minutes later, he fell asleep.
Until the end of his sheets adjusted slightly, signaling someone had sat down. That's when Sam opened his eyes to view you.
"Woah— what the—!" He scrambled around to hop off the bed, blade already out in case for protection. "Who the hell are you?"