It is narrated from the words of al-Bara ibn ‘Azib, may Allah be pleased with them both, that the Prophet (peace and blessings of Allaah be upon him) said:
“After the believer is seated in his grave and (angels) come to him, he will bear witness that there is no god (worthy of worship) but Allah, and that Muhammad is the messenger of Allah, for He said (the Most High): “ Allah will strengthen those who believed with a firm word … ” [1] ”. This hadith was narrated by al-Bukhari in 1369.
Sheikh al-Albani called the hadith authentic. See Saheeh al-jami ‘as-saghir 366.
Grade: Sahih
[1] Surah “Ibrahim” ayah 27.
Khadeeja