Taking the Lord's Name in Vain

The other day, I was folding laundry in my room and Aaron and Campbell were playing in her room. From over the monitor I heard Aaron exclaim, "Jesus, Campbell!"

In shock over him speaking like that I ran into the room to reprimand Aaron's language.

Me - Aaron, you are absolutely not to take our Lord's name in vain. Where did you learn to say that?

Aaron - from the book?

At that point I realized he was reading "Jesus and the 12 Dudes who Did" to his sister... And that I should probably observe a situation before starting my rants.