Suspicion can ruin relations between people, particularly when it is based on flimsy evidence, or hearsay. The Prophet (peace be upon him) spoke in very clear terms about misplaced suspicion, giving clear orders to refrain from it. The following authentic hadith groups together some of the actions that cause discord within the community and make people dislike one another:
Abu Hurayrah reports that the Prophet said: 'Beware of suspicion, for suspicion is the worst form of lying. Do not spy against one another, or compete with one another. Do not turn your back on one another, nor envy nor hate one another, but remain – you servants of God – brothers and sisters'. [Bukhari, Ahmad, Muslim]
This hadith stresses the importance of maintaining good relations within the Muslim community. The Prophet highlights certain things that would undermine such relations, and he tells us not to allow ourselves to indulge in them. Boycott, envy and hate should never be allowed to exist, let alone flourish in any Muslim community. Relations between Muslims should always be close. All members of the Muslim community should look at one another as brothers and sisters. They must value this tie of brotherhood, because it is established on the best basis, which is servitude to God and pure faith.
However, the hadith begins with a warning against suspicion describing it as the most untrue of speech. This is an apt description because whatever is said on the basis of suspicion has no basis in reality. It is all conjecture, leading to false accusations and ideas. It poisons relations and leads to discord and hostility. It also encourages what the Prophet mentions next, which is spying on one another. People do not spy on their neighbours or competitors unless they have some sort of suspicion they want to explore. Hence, they try to gather information secretly, perhaps through spying. This is again forbidden. The Prophet teaches us that we should help one another not to entertain any doubt leading to suspicion.
"Al-Adab al-Mufrad with Full Commentary: A Perfect Code of Manners and Morality" - Adil Salahi