―Quran 49:12

The believers are brothers, so reconcile between your brothers, and remain conscious of Allah, so that you may receive mercy.

O you who believe! No people shall ridicule other people, for they may be better than they. Nor shall any women ridicule other women, for they may be better than they. Nor shall you slander one another, nor shall you insult one another with names. Evil is the return to wickedness after having attained faith. Whoever does not repent — these are the wrongdoers.

O you who believe! Avoid most suspicion — some suspicion is sinful. And do not spy on one another, nor backbite one another. Would any of you like to eat the flesh of his dead brother? You would detest it. So remain mindful of Allah. Allah is Most Relenting, Most Merciful.

O people, indeed We have created you from male and female and made you peoples and tribes that you may know one another. The best among you in the sight of Allah is the most righteous. Allah is truly All-Knowing, All-Aware.

―Quran 49:10–13

It is not acceptable for a Muslim to spread rumors, or engage in backbiting of another person.