This is an old clip. Parts of the dialog are not clear, so we’re adding our own transcript here (may not be fully accurate):
starting at 00:13
Williamson (Magician): Murray, Murray, Murray. Now watch very closely. We have three cards….
Murray [interrupting]: No, there’s four! I can see another one under this one.
Audience: Laughing and applauding.
Later on -not in this video- Williamson goes on to say: That was my career Murray!
Here’s a video of their reunion some 20 years later.