What he said to a man praising someone
He repeated it several times.
وَيْحَكَ قَطَعْتَ عُنُقَ صَاحِبِكَ ـ يَقُولُهُ مِرَارًا ـ إِنْ كَانَ أَحَدُكُمْ مَادِحًا لاَ مَحَالَةَ فَلْيَقُلْ أَحْسِبُ كَذَا وَكَذَا
Wayḥaka qaṭaʿta ʿunuqa ṣāḥibik. In kāna aḥadukum mādiḥan lā maḥālata fa-l-yaqul: aḥsibu kadhā wa kadhā
Woe to you, you have cut your companion's neck. If one of you must praise, let him say: I think such and such.
Where this comes from
A man had been mentioned and someone praised him well. He gave the wording to use instead, and the reason: if he really believes it to be so, and his reckoner is Allah, and let no one declare anyone pure before Allah.
The full narration
Narrated Abu Bakra:A man was mentioned before the Prophet (ﷺ) and another man praised him greatly The Prophet (ﷺ) said, "May Allah's Mercy be on you ! You have cut the neck of your friend." The Prophet (ﷺ) repeated this sentence many times and said, "If it is indispensable for anyone of you to praise someone, then he should say, 'I think that he is so-and-so," if he really thinks that he is such. Allah is the One Who will take his accounts (as He knows his reality) and no-one can sanctify anybody before Allah." (Khalid said, "Woe to you," instead of "Allah's Mercy be on you)
Source
Ṣaḥīḥ al-Bukhārī · 6061
- Agreed upon as authentic (al-Bukhārī / Muslim)