لسانك حصانك، إن صنته صانك وإن خنته خانك

“Your tongue is your horse: if you protect it, it protects you, and if you betray it, it betrays you.”

Careful, honest speech serves and protects a person, while careless words bring harm.

— Traditional Saudi Arabia Wisdom, Saudi Arabia

Source: Traditional Saudi/Najdi proverb, public-domain oral tradition