It was narrated from 'Abdur-Rahman bin Abu Bakrah that his father said: "A man praised another man in the presence of the Messenger of Allah(saw). The Messenger of Allah(saw) said: 'Woe to you, you have cut the neck of your companion,' several times. Then he said: 'If anyone of you praises his brother, lethim say: "I think he is like this, but I do not sanctify anyone before Allah." (Sahih)