I would not let his people go because your serpent's tongue hardened my heart.
5 seconds sound clip from the The Ten Commandments (1956) movie soundboard.
You can hear this line at 02:54:21.647 in the Blu-ray version of the movie.
Quote context
[...]
- He is the first-born of Pharaoh.
- We have no skill before this... pestilence.
- My son.
- I would not let his people go because your serpent's tongue hardened my heart.
- You only thought to keep Moses here.
- You cared nothing for my throne, or my son.
- The shadow of death is on his face.
- Captain. Take my fastest chariot. Bring Moses to me.
- I will bring him, mighty Pharaoh.
[...]