Muhammad ibn Yazid al-Adami said: Abu Damrah narrated to us from Abu Hazim, from Sahl ibn Sa'd al-Sa'idi, that the Messenger of Allah, peace and blessings be upon him, said: ... and he mentioned it.

I say: This is an authentic chain of transmission. Its narrators are trustworthy and are among the narrators of the two Sahihs, apart from this al-Adami; yet he too is unquestionably trustworthy.

It has been corroborated, for Muhammad ibn Hammad said: Anas ibn 'Iyad al-Laythi narrated to us from Abu Hazim—from Sahl ibn Sa'd, as far as I know—with the same wording.

Al-Bayhaqi recorded it in Shu'ab al-Iman (7/260/10237).

This Muhammad ibn Hammad is likewise trustworthy: he is al-Abyurdi. Ibn Hibban declared him trustworthy (9/99 and 107), and a number of trustworthy narrators transmitted from him.

Imam Ahmad also corroborated them (5/331): Anas ibn 'Iyad narrated to us with the same wording.

The first part of it was recorded by al-Bukhari (4936, 5301, and 6530), Muslim (8/208), Ibn Hibban (6608, al-Ihsan edition), Ahmad (5/330, 335, and 338), al-Tabarani (5873, 5885, 5912, and 5988), and others, through various routes from Abu Hazim, with the same wording. It also has a corroborating narration from Anas in the two Sahihs, Ibn Hibban (6606), and others.

Another corroborating narration from Abu Hurayrah is found in al-Bukhari, Ibn Majah (2/375/3265), Ibn Hibban (6607), and others. *

3221—“I bear witness that none has the right to be worshipped but Allah, and that I am the Messenger of Allah. No servant who sincerely affirms these two testimonies will utter them except that Allah will protect him from the heat of the Fire.”

Abu Ya'la recorded it in his Musnad (1/199–200/230)—and this is his wording—,