Shaikhul-Islaam Ibn Taymiyyah (died 728 AH, rahimahullaah) said:
Yahyaa Ibn `Ammaar  said: Knowledge is of five kinds:
1. Knowledge that is the life of the World, and that is of the knowledge of Tawheed (the worship of Allaah alone, without any partners).
2. Knowledge that is the nourishment of the Religion, and that is the knowledge of reflecting upon the meanings of the Qur’aan and Hadeeth.
3. Knowledge that is the remedy of the Religion, and that is the knowledge of Fatwa; so if there befalls upon a worshipping servant an unexpected affliction, then he is in need of someone to cure him from that as Ibn Mas’ood said.
4. Knowledge that is the disease of the Religion, and that is the innovated and newly introduced speech.
5. Knowledge that is the destruction of the Religion, and that is the knowledge of magic and such things.
 He is Abu Zakariyaa Yahyaa Ibn `Ammaar ash-Shaybaanee, a resident of Haraat (a resident is called a Harawee), Khurasaan – modern day Herat in Afghanistan. He was an Imaam, Muhaddith and an admonisher in sermons. He was formidably skilful in Tafseer and the Sunnah. He died at the age of ninety. See Siyar A`laam an-Nubalaa 17/481, and Shadharaat adh-Dhahab 3/226.
Another famous Harawee is Shaikh al-Islaam Abu Ismaa`eel `Abdullaah Ibn Muhammad al-Ansaaree al-Harawee (born 396AH, rahimahullaah), from the lineage of the Companion Abu Ayyoob al-Ansaaree (radiyallaahu `anhu). He is the author of tremendous book Dhammul-Kalaam – a book in which he refuted the Ash`arees from ninety different angles!