A man praised another man in the presence of the Prophet ﷺ. The Prophet ﷺ said, "Woe to you, you have cut your brother's neck," repeating it three times. Then he said, "If any of you must praise someone, let him say, 'I reckon so-and-so to be such,' and Allah is his reckoner, and I do not declare anyone pure before Allah, if he truly knows him to be so."
أثنى رجل على رجل عند النبي ﷺ فقال: ويلك، قطعت عنق أخيك- ثلاثا-، من كان منكم مادحا لا محالة فليقل: أحسب فلانا، والله حسيبه، ولا أزكي على الله أحدا، إن كان يعلم.
Bukhari related it in Adab (6162), and Muslim in Zuhd and Raqaiq (3000), both through the route of Khalid Haddan, from Abdul-Rahman bin Abu Bakra, from his father, and he mentioned it.Whoever is praised by his companion should say, "O Allah, do not take me to task for what they say, and forgive me for what they do not know." This is how a man from the companions of the Prophet ﷺ would speak when he was praised. Bukhari related it in Adab al-Mufrad (761) with a sahih chain of transmission.