In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Ya’qoob Bin Sufyaan [rahimahullaah] said: I heard a person saying to Ahmad Bin Yoonus [rahimahullaah]: Is Abdullaah Al-Umariy a weak narrator of hadeeth? He [Ahmad] said: Indeed, he is weak. He is a Raafidi who harbours hatred towards his forefathers [i.e. the Salaf], and had you seen his beard, his graceful and fine physical [appearance], you would have conceded that he is trustworthy. Al-Haafidh Al-Khateeb al Baghdaadee [rahimahullaah] said: So, Ahmad Bin Yoonus used this as a proof that Abdullaah Al-Umari (appeared) trustworthy through that which was not a proof, because fine physical appearance is something shared between a trustworthy person and a disparaged person.”
Shaikhul Islaam Ibn Taymiyyah [rahimahullaah] stated in Ar-Radd Alal-Bakri: These ones [i.e. Bakri and others like him] have a religious and righteous appearance, but they are not from the people of knowledge- those who [possess] knowledge of the rulings of the religion, whose statements are accepted regarding the prescribed duties in Islaam and knowledge [regarding] what is lawful and unlawful. They [i.e. Bakri and those like him] neither have any legislated proofs with them nor a transmitted (text) from an approved scholar.
[Source: Quoted by Shaikh Abdullaah Bukhaari in At-Taliqaat Ar-Radiyyah Alal Mandhoomah Al-Bayqooniyyah: Lesson 1]