Allah commands His servant Muhammad () 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:

«لَا يُشِيرَنَّ أَحَدُكُمْ إِلَى أَخِيهِ بِالسِّلَاحِ، فَإِنَّهُ لَا يَدْرِي أَحَدُكُمْ لَعَلَّ الشَّيْطَانَ أَنْ يَنْزِعَ فِي يَدِهِ فَيَقَعَ فِي حُفْرَةٍ مِنَ النَّار»

(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.

[رَّبُّكُمْ أَعْلَمُ بِكُمْ إِن يَشَأْ يَرْحَمْكُمْ أَوْ إِن يَشَأْ يُعَذِّبْكُمْ وَمَآ أَرْسَلْنَـكَ عَلَيْهِمْ وَكِيلاً - وَرَبُّكَ أَعْلَمُ بِمَنْ فِى السَّمَـوَتِ وَالاٌّرْضِ وَلَقَدْ فَضَّلْنَا بَعْضَ النَّبِيِّينَ عَلَى بَعْضٍ وَءَاتَيْنَا دَاوُودَ زَبُورًا ]

(54. Lord knows you best; if He wills, He will have mercy on you, or if He wills, He will punish you. And We have not sent you as a guardian over them.) (55. And your Lord knows best all who are in the heavens and the earth. And indeed, We have preferred some of the Prophets above others, and to Dawud We gave the Zabur.) Allah says:

[رَّبُّكُمْ أَعْلَمُ بِكُمْ]

(Your Lord knows you best;) O mankind, meaning, He knows best who among you deserves to be guided and who does not deserve to be guided.

[إِن يَشَأْ يَرْحَمْكُمْ]

(if He wills, He will have mercy on you,) by helping you to obey Him and turn to Him.

[أَوْ إِن يَشَأْ يُعَذِّبْكُمْ وَمَآ أَرْسَلْنَـكَ]

(or if He wills, He will punish you. And We have not sent you) - O Muhammad -

[عَلَيْهِمْ وَكِيلاً]

(as a guardian over them.) meaning, `We have sent you as a warner, so whoever obeys you, will enter Paradise and whoever disobeys you, will enter Hell.'

[وَرَبُّكَ أَعْلَمُ بِمَنْ فِى السَّمَـوَتِ وَالاٌّرْضِ]

(And your Lord knows best all who are in the heavens and the earth.) meaning, their status or level of obedience or disobedience.