مَنْ عَمِلَ صَـٰلِحًا فَلِنَفْسِهِ ۖ وَمَنْ أَسَآءَ فَعَلَيْهَا ۖ ثُمَّ إِلَىٰ رَبِّكُمْ تُرْجَعُونَ

Those who do not firmly believe that the Day of Judgement is going to dawn on them, venture to oppress others. They harass the preacher of Truth in every possible way. At that time feelings of revenge may develop in the heart of the preacher, but he should be forgiving towards his addressees. He should concentrate all his attention on the work of his mission and leave the matter of dealing with others’ evil deeds in the hands of God. The value of the preacher’s efforts is not assessed on the basis of the number of persons he has influenced and brought on to the path of Truth. The value of his performance in the eyes of God depends upon the extent to which he remained steadfastly dedicated to the Truth; and to what degree he himself exemplified the behaviour expected of him.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (45:15)