Al perro que duerme, ¡¡¡no lo despiertes!!!

 …LET SLEEPING DOGS LIE…

If someone is told to let sleeping dogs lie, it means that they shouldn’t disturb a situation as it would result in trouble or complications.

Refrain from disturbing people or from debating topics not currently causing one any trouble.

Example: It may be that he used to live with Miss Bloggs; but I don’t think you ought to refer to that topic in front of his wife – it’s better to let sleeping dogs of that sort lie.

Other Proverbs

Gallina vieja hace buen caldo
Haciendo y deshaciendo se va aprendiendo
Si hay trato, pueden ser amigos perro y gato
El tiempo todo lo cura