It is narrated from Hazrat Abu Bakrah (may Allah be pleased with him) that once, in the presence of the Prophet (peace and blessings be upon him), a man praised another man. The Prophet (peace and blessings be upon him) said, "Alas! You have broken your companion’s neck." And he said, "If you must praise your brother, then you should say: 'So-and-so appears to be such-and-such, and I do not declare anyone pure before Allah, and Allah is his true guardian; I consider him to be so.'"