Sayyiduna Abu Bakrah (may Allah be pleased with him) narrates: A man praised another man in the presence of the Prophet Muhammad (peace and blessings be upon him), so the Prophet (peace and blessings be upon him) said: "Woe to you! You have cut your brother's neck." He (peace and blessings be upon him) said this several times. Then he (peace and blessings be upon him) said: "When any of you has to praise his brother, he should say: 'I think such and such about this person, and Allah is his guardian,' (and these words should also be used) when a person knows that the other is really like that."