The Four you mustn't take Knowledge From

Muhammad ibn Ismaa’eel narrated to us, that Ibraheem ibn al-Mundhir narrated to him, that Ma’een ibn ‘Isa said:

Maalik ibn Anas used to say:

Knowledge must not be taken from four types of people, and can be taken from other than them:

1. A foolish person whose foolishness is known, even if he narrates the most Ahadeeth amongst people.
2. A liar who lies about people’s narrations if this is known about him, even if he is not accused of lying upon the Messenger - .
3. One who follows his desires/an innovator who calls the people to his desires/innovations.
4. A Shaykh who has virtue and worship if he does not know Hadeeth.