In the Quran and Sunnah we have been strongly advised to abstain from these vices:

“O You who Believe! Avoid much suspicion. Indeed some suspicions are sins.” (Surah Hujurat Verse 12)

Hazrat Abu Hurairah (RA) narrates that Rasulullah (Sallallahu Alaihi Wasallam) said, “Abstain from suspicion. Verily a baseless suspicion is the greatest lie.” (Musnad Ahmad)

Furthermore, the Quran implores us to have good thoughts about our fellow Muslim brothers:

“Why did the believing men and women not think good of their own people when they heard the slander?” (Surah Noor Verse 12)

A Muslim should adopt a good opinion of others and abstain from suspicions. It will save us from misery and many other sins.