Mishkat al-Masabih 2163
‘Abdullah b. Khubaib said:
We went out one rainy and intensely dark night to look for God’s messenger, and when we caught up on him he said to me, “Say.” I asked him what I was to say, and he replied, “If you recite ‘Say, He is God, One’ and al-Mu'awidhatān (The last 3 sūras of the Qur’ān) three times morning and evening, they will serve you for every purpose.” 

Tirmidhī, Abū Dāwūd and Nasā’i transmitted it.
وَعَنْ عَبْدِ اللَّهِ بْنِ خَبِيبٍ قَالَ: خَرَجْنَا فِي لَيْلَةِ مَطَرٍ وَظُلْمَةٍ شَدِيدَةٍ نَطْلُبُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَأَدْرَكْنَاهُ فَقَالَ: «قُلْ» . قُلْتُ مَا أَقُولُ؟ قَالَ: « (قُلْ هُوَ اللَّهُ أَحَدٌ)
وَالْمُعَوِّذَتَيْنِ حِينَ تُصْبِحُ وَحِينَ تُمْسِي ثَلَاثَ مَرَّاتٍ تَكْفِيكَ مِنْ كُلِّ شَيْءٍ» . رَوَاهُ التِّرْمِذِيُّ وَأَبُو دَاوُدَ وَالنَّسَائِيُّ