Imām Aḥmad رحمه الله said:
“DO NOT write from three:
• A PERSON OF INNOVATION* who calls to his Bidʿah.
• Or a LIAR for indeed nothing is written from him; be it less or a lot.
• Or from a man who makes a mistake but DOES NOT RECTIFY it when he is refuted.”
[الكافية ١٤٤]