Anas bin Malik reported,

The companions of the Prophet ﷺ mentioned Malik bin al-Dukhshum in the presence of the Messenger of Allah ﷺ, speaking ill of him and insulting him.The Messenger of Allah ﷺ said, "Leave my companions alone."They said, "Messenger of Allah, he is a refuge for the hypocrites and a shelter to which they turn."The Messenger of Allah ﷺ asked, "Does he not testify that there is no god but Allah and that I am the Messenger of Allah?"They replied, "Yes, but there is no good in his testimony."The Messenger of Allah ﷺ said, "No servant testifies to it sincerely from his heart and then dies upon that, except that Allah forbids him to the Fire."

Azami 9820

Sahih

عن أنس بن مالك قال

ذكر أصحاب النبي ﷺ مالك بن الدخشم عند رسول الله ﷺ، فوقعوا فيه، وشتموه فقال رسول الله ﷺ: دعوا لي أصحابي فقالوا: يا رسول الله، إنه كهف المنافقين و ملجؤهم الذي يلجؤون إليه، فقال رسول الله ﷺ: أليس يشهد أن لا إله إلا الله، وأني رسول الله؟ قالوا: بلى، ولا خير في شهادته، فقال رسول الله ﷺ: لا يشهد بها عبد صادقا من قلبه، ثم يموت على ذلك، إلا حرمه الله على النار.

الأعظمي 9820صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Virtues of the Companions and reports about them
Chapter
Virtue of companionship
Section
Prohibition of insulting the Companions
Numbering
Jami al-Kamil 9820 (2nd edition)
Azami 9820