It was narrated from Mu'adh bin 'Abdullah that his father said:

"It was raining and dark, and we were waiting for the Messenger of Allah ﷺ to lead us in prayer. Then the Messenger of Allah ﷺ came out to lead us in prayer and he said: 'Say.' I said: 'What should I say?' He said: 'Say: He is Allah, (the) One and Al-Mu'awwadhatain in the evening and in the morning, three times, and that will suffice you against everything.'"

أَخْبَرَنَا أَبُو عَبْدِ الرَّحْمَنِ، أَحْمَدُ بْنُ شُعَيْبٍ قَالَ أَنْبَأَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا أَبُو عَاصِمٍ، قَالَ حَدَّثَنَا ابْنُ أَبِي ذِئْبٍ، قَالَ حَدَّثَنِي أَسِيدُ بْنُ أَبِي أَسِيدٍ، عَنْ مُعَاذِ بْنِ عَبْدِ اللَّهِ، عَنْ أَبِيهِ، قَالَ أَصَابَنَا طَشٌّ وَظُلْمَةٌ فَانْتَظَرْنَا رَسُولَ اللَّهِ ﷺ لِيُصَلِّيَ بِنَا ثُمَّ ذَكَرَ كَلاَمًا مَعْنَاهُ فَخَرَجَ رَسُولُ اللَّهِ ﷺ لِيُصَلِّيَ بِنَا فَقَالَ " قُلْ " . فَقُلْتُ مَا أَقُولُ قَالَ " { قُلْ هُوَ اللَّهُ أَحَدٌ } وَالْمُعَوِّذَتَيْنِ حِينَ تُمْسِي وَحِينَ تُصْبِحُ ثَلاَثًا يَكْفِيكَ كُلَّ شَىْءٍ " .