How did he know??

Today Joseph and I were eating lunch together. Soon I was finished, and he was still working on his, so I reached for the Bible that happened to be sitting on the table and turned to a reading for an Easter Monday meditation. Joseph started to reach for the book and indicate that he wanted it, so I said, "I'll read to you." I started reading. I didn't say "let's pray" or make a sign of a cross or anything. A few lines into the reading, Joseph stopped what he was doing and folded his hands to pray! I don't know how he knew!! Maybe he was clued in when I read the name "Jesus," but I really didn't say or do anything else to indicate it was a religious reading. He also made a gesture that I think was his sign of the cross (usually taps on one or both of his shoulders) and he folded his hands again! I am just amazed!