Musnad Ahmad 1010:0

Narrated to us by Muhammad ibn Ja’far, who said: Narrated to us Shu’bah, from Yazid ibn Khusayfah, who said: I heard Muhammad ibn ‘Abd al-Rahman ibn Thawban narrating from Muhammad ibn ‘Abd Allah ibn Khubayb, from his father, ‘Abd Allah ibn Khubayb, who said: We went out on a rainy night and in intense darkness, seeking the Messenger of Allah (ﷺ) to pray for us. We found him, and he said: "Have you prayed?" I did not say anything. He said: "Say." I did not say anything. He said: "Say." I did not say anything. He said: "Say." I said: "O Messenger of Allah, what should I say?" He said: "Say: 'He is Allah, [who is] One' (Surah Al-Ikhlas) and the two chapters of seeking refuge (Al-Mu'awwidhatayn) when you enter the evening and when you enter the morning, three times. They will suffice you against everything."