I have only to feel the blade to know which side.
3 seconds sound clip from the The Fall of the Roman Empire (1964) movie soundboard.
You can hear this line at 00:59:26.858 in the Blu-ray version of the movie.
Quote context
[...]
- And then, long live the emperor, Commodus.
- It could be done before hundreds of witnesses. No one could be suspected.
- From whom will Caesar accept fruit? Who is close enough to him?
- I am.
- I have only to feel the blade to know which side.
- And who better than a blind man?
- Are you a man to enjoy an irony, Marcus Aurelius?
- Look well then at the emperor of all Rome become no better than a slave.
- And who or what is your master? Slave!
- A small point in your side. Perhaps no larger than a grain of wheat.
[...]