Sahih Muslim 7501
صحيح مسلم#7501SahihAbd al-Rahman b. Abu Bakra reported on the authority of his father that a person praised another person in the presence of Allah's Apostle (ﷺ), whereupon he said:Woe be to thee, you have broken the neck of your friend, you have broken the neck of your friend-he said this twice. If one of you has to praise his friend at all, he should say: I think (him to be) so and Allah knows it well and I do not know the secret of the heart and Allah knows the destined end, and I cannot testify his purity against Allah but (he appears) to be so and so
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih Muslim is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 55:83