proverb/wa.ɲe vi.lɛ̃ | il vu pwɛ̃.dʁa | pwa.ɲe vi.lɛ̃ | il vu.z‿wɛ̃.dʁa/
if you behave kindly towards a bad person, they will be mean; conversely, if you behave spitefully, they will be kind to you
From oindre (“to anoint”) and poindre (“to prick”). For the meaning, compare English treat them mean, keep them keen.