Atha' bin Abi Rabah

Atha' bin Abi Rabah, despite being born as a black slave with a weak physical condition, grew up to become the most trusted mufti (fatwa giver) in Mecca in his time, referred to by Hajj pilgrims from all corners of the Islamic world. He learned directly from hundreds of companions of the Prophet ﷺ who were still alive during his time, making his knowledge very broad and deep even though his background was simple - an example that the glory of knowledge knows no social status.