۞ قُلۡ إِنَّمَآ أَعِظُكُم بِوَٰحِدَةٍۖ أَن تَقُومُواْ لِلَّهِ مَثۡنَىٰ وَفُرَٰدَىٰ ثُمَّ تَتَفَكَّرُواْۚ مَا بِصَاحِبِكُم مِّن جِنَّةٍۚ إِنۡ هُوَ إِلَّا نَذِيرٞ لَّكُم بَيۡنَ يَدَيۡ عَذَابٖ شَدِيدٖ ٤٦
Say, "I only advise you of one [thing] - that you stand for Allāh, [seeking truth] in pairs and individually, and then give thought." There is not in your companion any madness. He is only a warner to you before a severe punishment.
Translation: Saheeh International (English)
Each word's meaning and sound
Say - O Messenger, to these idolaters: “I only direct you to and advise you of one characteristic, which is that you stand free from desires, for Allah’s sake, in twos and individually, then think about the life of your companion and what you know of his intelligence, truthfulness and trustworthiness”, so that it becomes clear to you that he (peace be upon him) is not insane. He is not but a warner to you before a severe punishment, if you do not repent to Allah from associating partners with Him.
Al-Mukhtasar in interpreting the Noble Quran