Before you assume the worst of someone
Three things forbidden in sequence, and they escalate.
يَـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُوا۟ ٱجْتَنِبُوا۟ كَثِيرًا مِّنَ ٱلظَّنِّ إِنَّ بَعْضَ ٱلظَّنِّ إِثْمٌ ۖ وَلَا تَجَسَّسُوا۟ وَلَا يَغْتَب بَّعْضُكُم بَعْضًا ۚ أَيُحِبُّ أَحَدُكُمْ أَن يَأْكُلَ لَحْمَ أَخِيهِ مَيْتًا فَكَرِهْتُمُوهُ ۚ وَٱتَّقُوا۟ ٱللَّهَ ۚ إِنَّ ٱللَّهَ تَوَّابٌ رَّحِيمٌ
Yā ayyuha-lladhīna āmanu-jtanibū kathīran mina-ẓ-ẓann, inna baʿḍa-ẓ-ẓanni ithm, wa lā tajassasū wa lā yaghtab baʿḍukum baʿḍā…
“O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin. And do not spy or backbite each other. Would one of you like to eat the flesh of his brother when dead? You would detest it. And fear Allāh; indeed, Allāh is Accepting of Repentance and Merciful.”
Suspicion, then spying, then talking. The verse forbids the first because it leads to the others.
Source
The Qur'an · 49:12
- Qur'anic text in the Uthmani script via Quran.com; translation: Saheeh International