Translation of the verse 55 from Surah Adh-Dhariyat : Number of verses 60 - - page 523 - Part 27.
And remind (by preaching the Quran, O Muhammad SAW) for verily, the reminding profits the believers.
And remind, for indeed, the reminder benefits the believers.
(51:55) Do, however, keep exhorting them; for exhortation benefits those endowed with faith. *52
*52) The Holy Prophet has not been addressed here to be taught this method because, God forbid, in his preaching he unnecessarily pursued the people and Allah wanted to stop him from this fact, the actual reason for stating this method is that when a preacher of the truth has done his best to make the people understand his message in a rational way and then seeing the signs of stubbornness in them withdraws from them, the people inveigh against him and start accusing him of indifference and inattention whereas, they, as they say, want to discuss things in order to understand his message. The fact, however, is that they do not intend to understand anything but only to involve the preacher in disputation and waste his time. Therefore, Allah Himself said in clear words: "Turn away from them: you are not at all to blame for showing any indifference towards them." After this nobody could blame the Holy Prophet that according to the Book that he had brought he had been appointed to make them understand his religion: then why he did not answer their objections.
Source : Adh-Dhariyat Verse 55: And remind, for indeed, the reminder benefits the believers.