if you don't see any evil, or hear any evil, or speak any evil, it won't exist in your world.
It means if you are not exposed to bad things, you will not do bad things.
That actually is the full saying.
It was journeyman director. Arthur Hiller, who also did The Out of Towners, Love Story and the In Laws before the seventies ended and he retired from good movies.
Oiga que ningún mal no hablar ningún mal no vea ningún mal.