In The Name of Allah, The Most Merciful, The Bestower of Mercy.

Al-Allamah Saalih Al-Fawzan, may Allah preserve him, stated:

Amr Ibnul Aas, may Allah be pleased with him, was one of those given authority and so was Abu Ubaydah Ibn Al-Jarraah, may Allah be pleased with him. Khalid Bin Al-Waleed, may Allah be pleased with him, was given preference over them due to his bravery and usefulness in Jihad. When Abu Bakr, may Allah be pleased with him, passed away, Umar Ibnul Khattab, may Allah be pleased with him, gave Abu Ubaydah authority over all of them because Umar Ibnul Khattaab used to be tough for the sake of Allah, thus, he appointed Abu Ubaydah because he was soft; Abu Bakr was soft and Khalid was tough. Therefore, the soft one gave authority to the tough one and the tough one gave authority to the soft one to balance the affairs.

An Excerpt from “Adwaa Min Fataawaa Shaikhul Islaam Ibn Taymiyyah”. 2/568-569