وَلَا تَسْتَوِي الْحَسَنَةُ وَلَا السَّيِّئَةُ ۚ ادْفَعْ بِالَّتِي هِيَ أَحْسَنُ فَإِذَا الَّذِي بَيْنَكَ وَبَيْنَهُ عَدَاوَةٌ كَأَنَّهُ وَلِيٌّ حَمِيمٌ

The call of the Quran is to invite people to God. Bringing man closer to his Lord and Sustainer; making him spend his whole life in remembrance of God; developing a feeling in man that he should make the one and only God the centre of his attention—these are the real aims of the Quranic call and undoubtedly there is no call better than this. But, only that person becomes the preacher of God who is so sincere in his call that he, first of all, accepts whatever he wants others to accept. Whatever he exhorts others to do, he should have himself started doing from the outset. The greatest weapon of a preacher of Truth is his ability to treat people well. Even if people are not good to him, he should be good to them. He should adopt the policy of avoidance in the face of provocation or irritating behaviour and exercise patience under trying circumstances. Almighty God has made it possible for unilateral good behaviour to be immensely persuasive. The preacher of God is aware of this God-given asset, and uses it to the utmost extent, even although it may involve crushing his own feelings and killing the urge to retaliate. Whenever a caller to Truth has the feeling within him that it is necessary for him to retaliate against a particular instance of oppression in order to prevent the enemy from becoming so bold as to commit even greater excesses, he should immediately understand that this is a satanic inducement. It is the duty of every believer and preacher of Truth to seek the protection of God from such feelings instead of acting upon them.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (41:34)