Surah Al-Hujurat (The Private Quarters), Verse 6

یٰۤاَیُّهَا الَّذِیْنَ اٰمَنُوْۤا اِنْ جَآءَكُمْ فَاسِقٌ بِنَبَاٍ فَتَبَیَّنُوْۤا اَنْ تُصِیْبُوْا قَوْمًا بِجَهَالَةٍ فَتُصْبِحُوْا عَلٰی مَا فَعَلْتُمْ نٰدِمِیْنَ ۟

Yaaa ayyuhal lazeena aamanoo in jaaa'akum faasiqum binaba in fatabaiyanooo an tuseeboo qawmam bijahalatin fatusbihoo 'alaa maa fa'altum naadimeen

“O ye who believe! If a wicked person comes to you with any news, ascertain the truth, lest ye harm people unwittingly, and afterwards become full of repentance for what ye have done.”

Quran 49:6 (Yusuf Ali Translation)