When Prophet Muhammad صلى الله عليه و سلم appointed Mu'adh ibn Jabal رضي الله عنه as governor of Yemen, he asked him, "How will you decide the affairs of the people?"
Mu'adh رضي الله عنه answered, "O Messenger of Allah, I will decide according to the teachings of the Qur'an."
"If you do not find the answer to the Qur'an," The Prophet صلى الله عليه و سلم asked him, "what will you do then?"
"I will seek advice from your tradition, O Messenger of Allah," replied Mu'adh رضي الله عنه.
The Prophet Muhammad صلى الله عليه و سلم asked him again, "If you do not find an answer in my tradition, what will you do then?"
Mu'adh رضي الله عنه replied, "I will then use my best judgement."
The Prophet's face gleamed with joy. He then remarked, "Blessed be Allah Who has given wisdom to a messenger of His messenger."
[Source: Stories of the Sirah Vol.6 - The Teacher of Mankind]
