that the Prophet ﷺ said: "Some Ayat have been revealed to me the likes of which have not been seen: Qul A'udhu Birabbin-Nas until the end of the Surah and Qul A'udhu Birabbil-Falaq until the end of the Surah."  

عَنِ النَّبِيِّ ﷺ قَالَ قَدْ أَنْزَلَ اللَّهُ عَلَىَّ آيَاتٍ لَمْ يُرَ مِثْلُهُنَّ (قُلْ أَعُوذُ بِرَبِّ النَّاسِ ) إِلَى آخِرِ السُّورَةِ وَ (قُلْ أَعُوذُ بِرَبِّ الْفَلَقِ ) إِلَى آخِرِ السُّورَةِ  

"The Messenger of Allah ﷺ ordered me to recite Al-Mu'awwidhatain at the end of every Salat."  

أَمَرَنِي رَسُولُ اللَّهِ ﷺ أَنْ أَقْرَأَ بِالْمُعَوِّذَتَيْنِ فِي دُبُرِ كُلِّ صَلاَةٍ