And say to My slaves (i.e. the true believers of Islamic Monotheism) that they should (only) say those words that are the best. (Because) Shaitan (Satan) verily, sows disagreements among them. Surely, Shaitan (Satan) is to man a plain enemy.
Chapter 17 Al-‘Isrā : Verse 53
People should speak Good Words with Politeness
Allah commands His servant Muhammad ( Peace and blessings be upon him ) to tell the believing servants of Allah that they should address one another in their conversations and discussions with the best and politest of words, for if they do not do that, Shaytan will sow discord among them, and words will lead to actions, so that evil and conflicts and fights will arise among them. For Shaytan is the enemy of Adam and his descendants, and has been since he refused to prostrate to Adam. His enmity is obvious and manifest. For this reason it is forbidden for a man to point at his Muslim brother with an iron instrument, for Shaytan may cause him to strike him with it. (Imam Ahmad recorded that Abu Hurayrah said: “The Messenger of Allah said:
(No one of you should point at his brother with a weapon, for he does not know whether Shaytan will cause him to strike him with it and thus be thrown into a pit of Fire.) Al-Bukhari and Muslim recorded this Hadith with the chain of narration from `Abdur-Razzaq.