Surah Al-Isra' (The Night Journey), Verse 82

وَنُنَزِّلُ مِنَ الْقُرْاٰنِ مَا هُوَ شِفَآءٌ وَّرَحْمَةٌ لِّلْمُؤْمِنِیْنَ وَلَا یَزِیْدُ الظّٰلِمِیْنَ اِلَّا خَسَارًا ۟

Wa nunazzilu minal quraani maa huwa shifaaa'unw wa rahmatullil mu'mineena wa laa yazeeduz zaalimeena illaa khasaaraa

“We send down (stage by stage) in the Qur'an that which is a healing and a mercy to those who believe: to the unjust it causes nothing but loss after loss.”

Quran 17:82 (Yusuf Ali Translation)