Surat Al Isra' (53-54)

{وَقُل لِّعِبَادِي يَقُولُواْ الَّتِي هِيَ أَحْسَنُ إِنَّ الشَّيْطَانَ يَنزَغُ بَيْنَهُمْ إِنَّ الشَّيْطَانَ كَانَ لِلإِنْسَانِ عَدُوّاً مُّبِيناً} (الإسراء : 53)

53- And tell My Believing Servants to have softness in their words and dialogue with others, to say a kind word, and choose the best and polite words to affect souls greatly, be more influential, and most responsive. Satan waits for errors to magnify them and make them a reason for enmity and hatred among believers while he is a manifest foe to them. Good word keeps him away from the assemblies and talks of good people, so they will be in harmony and intimacy, and away from his whispers and plots.

{رَّبُّكُمْ أَعْلَمُ بِكُمْ إِن يَشَأْ يَرْحَمْكُمْ أَوْ إِن يَشَأْ يُعَذِّبْكُمْ وَمَا أَرْسَلْنَاكَ عَلَيْهِمْ وَكِيلاً} (الإسراء : 54)

54- You lord knows exactly what is hidden in your souls and knows the readiness of each one of you and his willingness to guidance or error. So when He wills, He shall bestow mercy on you and guide you to faith, and if He wills, He shall torture you for your disbelief and error by His Knowledge and Wisdom. {And your lord does not wrong anyone} [Surat Al kahf: 94]. O Prophet, We have not made you a guardian to guide polytheists or fix their hearts, but you are a warner and an informer.