How authentic is the Hadith: "O Allah, as I have entered the morning, I bear witness to You, and to the bearers of Your Throne, Your angels, and all of Your creation, that indeed You are Allah, there is no god but You, alone, without partner, and that Muhammad is Your servant and Your Messenger"?

The hadith (definition) is Hasan (definition) (good). It was graded Hasan by Ibn Al-Qayyim, Al-Diya' Al-Maqdisi, and Al-Hafiz Ibn Hajar. Al-Nawawi deemed its chain of transmission Jayyid (good). It is narrated from Anas ibn Malik, may Allah be pleased with him, and has two chains of transmission from him:

The first chain: Narrated by Abu Dawud, Al-Tirmidhi, Al-Diya', and others from Baqiyyah ibn Al-Walid, from Muslim ibn Ziyad, from Anas ibn Malik, from the Messenger of Allah, peace and blessings be upon him, who said: "Whoever says when he wakes up: 'O Allah, as we wake up, we bear witness to You and bear witness to the bearers of Your Throne, Your angels, and all Your creation, that You are Allah, there is no god but You alone, without partner, and that Muhammad is Your servant and Your Messenger,' Allah will forgive him whatever sins he committed on that day. And if he says it when he reaches the evening, Allah will forgive him whatever sins he committed on that night."

The second chain: Narrated by Abu Dawud, Al-Nasa'i, Ibn Al-Sunni, and others from Muhammad ibn Isma'il ibn Abi Fudayk, who said: Abd Al-Rahman ibn Abd Al-Majid narrated to me, from Hisham Al-Ghazi, from Makhul, from Anas ibn Malik, with a similar meaning.

It has a supporting narration from the hadith of Abu Sa'id Al-Khudri, but its chain of transmission is weak. It also has another supporting narration from the hadith of Salman Al-Farsi, but it is not restricted to morning and evening.