Musnad Ahmad 830:50

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Khalid al-Hadhdha’, from ‘Abd al-Rahman ibn Abi Bakrah, from his father, from the Prophet (peace and blessings of Allah be upon him), that they mentioned a man in his presence. A man said: "O Messenger of Allah, there is no man after the Messenger of Allah (peace and blessings of Allah be upon him) better than him in such and such." The Prophet (peace and blessings of Allah be upon him) said: "Woe to you, you have cut the neck of your companion," repeating that several times. The Messenger of Allah (peace and blessings of Allah be upon him) said: "If one of you must praise his brother, let him say: 'I consider such-and-such to be so,' if he believes he is like that, and I do not purify anyone before Allah, and his reckoner is Allah, 'I consider him to be such-and-such.'"