What goes around comes around
unatʃopanda nditʃo utakatʃovuna
In Swahili Unachopanda ndicho utakachovuna.
This idiom is a common proverb about the consequences of one's actions.
Example
"Alisema uongo, na sasa hakuna anayemwamini. Unachopanda ndicho utakachovuna."