closer to Allah and His Messenger than he is. Intercession, meanwhile, is founded upon mercy and seeking good for others, and this cannot be found in someone who frequently curses them and refrains from supplicating for them.”1.
A Muslim should therefore supplicate for his Muslim brothers, love good for them, and refrain from cursing, insulting, or maligning them, for such conduct is neither befitting of a Muslim nor part of his character.
Al-Hākim narrated from Abd Allah ibn Umar—may Allah be pleased with them both—that the Messenger of Allah—peace and blessings be upon him—said: “It is not fitting for a believer to be given to cursing.”2.
Imam Ahmad and al-Tirmidhī narrated from Abd Allah ibn Masūd—may Allah be pleased with him—that the Prophet—peace and blessings be upon him—said: “The believer is not one who maligns others, habitually curses, uses obscene speech, or is foul-mouthed.”3.
It is also authentically established in Sahīh al-Bukhārī and Sahīh Muslim that the Prophet—peace and blessings be upon him—said: “A Muslim is one from whose tongue and hand other Muslims are safe.”4. The hadiths conveying this meaning are numerous.
This is the very least expected of a Muslim: if he does not supplicate for his Muslim brothers, do good to them, and strive to meet their needs and advance their interests, then he must at least refrain from harming them or bringing evil upon them.