وَقُل لِّعِبَادِي يَقُولُوا الَّتِي هِيَ أَحْسَنُ ۚ إِنَّ الشَّيْطَانَ يَنزَغُ بَيْنَهُمْ ...

This verse alludes to the delicate relationship between the preacher and his addressees. However provocative the addressees may be, the preacher has been commanded to exercise patience and refrain from repaying in the same coin. For, if he is provoked by the addressees’ ill behaviour, an atmosphere of hatred and obstinacy will develop. This tension between the preacher and the addressees might make it impossible for the latter to take his message cool-mindedly, with an open and unbiased mind. Any atmosphere of hatred and obstinacy between the preacher and the addressees favours Satan, who is thus able to make the call of truth unpalatable to the addressees. Therefore, if the preacher through any of his actions becomes responsible for producing a feeling of defiance and hatred, it is as if he were playing into the hands of Satan. It is like doing the enemy’s job oneself.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (17:53)