Dan Brown "Who Said That?" Challenge

Ok, so here is a new series on Dan Brown Portal. The "Who Said That?" challenge. It's very simple. I will share a quote from a Dan brown book, you have to tell me:

1. Which of Dan Brown's novels it is found in, and

2. Who said it?

Let's see how well you know Dan Brown's books! Here's today's quote:

"Set down your gun and radio...or I'll put my knee through this painting."

Good luck and leave your answers in a comment.