And with this chain, from al-Ḥussain bin Sayf, from his father, from ʿUmar bin Shimr, from Jābir, from Abī Jaʿfar عليه السلام who said:

The Messenger of Allāh صلى الله عليه وآله said: “Dictate to your moribund ‘There is no god but Allāh’, because it obliterates sins.”
They said: “Oh Messenger of Allāh, and what of those who say it while in good health?”
He said: “That crushes more and more [sins]. Verily, [the phrase] ‘There is no god but Allāh’ is a source of tranquility to the heart (‘uns) for the believer during his lifetime, and at his death and the day he resurrects.”
The Messenger of Allāh صلى الله عليه وآله also said: “Jibrā’īl عليه السلام said: ‘Oh Moḥammed, if you were to see them when they are resurrected, one whose face is whitened calls out: ‘There is no god but Allāh, and Allāh is greater (Allāhu Akbar)’, and one whose face is blackened calling out: ‘Oh Woe onto me, Oh the perdition!’

وبهذا الاسناد، عن الحسين بن سيف عن أبيه عن عمر بن شمر عن جابر عن أبي جعفر عليه السلام قال: قال رسول الله صلى الله عليه وآله لقنوا موتاكم لا إله إلا الله فإنها تهدم الذنوب، فقالوا يا رسول الله فمن قال في صحته؟ فقال ذاك أهدم وأهدم، إن لا إله إلا الله أنس للمؤمن في حياته وعند موته وحين يبعث وقال رسول الله صلى الله عليه وآله قال جبرئيل عليه السلام يا محمد لو تراهم حين يبعثون هذا مبيض وجهه ينادي لا إله إلا الله والله أكبر، وهذا مسود وجهه ينادي يا ويلاه يا ثبوراه.