Sunan an-Nasa'i, Book 50, Hadith 2 (In-Book) ⓘ
It was narrated from Mu'adh bin 'Abdullah bin Khubaib that his father said: "I was with the Messenger of Allah [SAW] on the road to Makkah when I found myself alone with the Messenger of Allah [SAW]. I drew close to him and he said: 'Say.' I said: 'What should I say?' He said: 'Say.' I said: 'What should I say?' He said: 'Say: I seek refuge with (Allah) the Lord of the daybreak...' until he finished (the Surah), then he said: 'Say: I seek refuge with (Allah) the Lord of mankind...' until he finished it. Then he said: 'The people cannot seek refuge with Allah by means of anything better than these two.'"
أَخْبَرَنَا يُونُسُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا ابْنُ وَهْبٍ، قَالَ أَخْبَرَنِي حَفْصُ بْنُ مَيْسَرَةَ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ مُعَاذِ بْنِ عَبْدِ اللَّهِ بْنِ خُبَيْبٍ، عَنْ أَبِيهِ، قَالَ كُنْتُ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فِي طَرِيقِ مَكَّةَ فَأَصَبْتُ خَلْوَةً مِنْ رَسُولِ اللَّهِ صلى الله عليه وسلم فَدَنَوْتُ مِنْهُ فَقَالَ " قُلْ " . فَقُلْتُ مَا أَقُولُ قَالَ " قُلْ " . قُلْتُ مَا أَقُولُ قَالَ " { قُلْ أَعُوذُ بِرَبِّ الْفَلَقِ } " . حَتَّى خَتَمَهَا ثُمَّ قَالَ " { قُلْ أَعُوذُ بِرَبِّ النَّاسِ } " . حَتَّى خَتَمَهَا ثُمَّ قَالَ " مَا تَعَوَّذَ النَّاسُ بِأَفْضَلَ مِنْهُمَا " .
also referenced under: Hadith 5429 (Reference) & Volume 6, Book 50, Hadith 5431 (DarusSalam)