Question: I once saw this thought tha I can’t find the source for: “If you do not stop evil, it will multiply”. Thanks
Answer: That exact phraseology does not sound familiar. The Sages do teach with regards to our base nature (Yetzer Hora) that if you feed it, it is starving, and if you starve it, it is sated. That is a similar notion.
Rabbi Chayim Lando