This principle, derived from the Qur'an, the Sunnah and Ijma' of the
Sahabah, can be extracted from two different angles:
a. Obedience to the head of the Islamic State is an obligation on Muslims.
b. Looking after the affairs of the Muslims is an obligation on the head
of State.
The first point: Obeying the head of the Islamic State is an obligation on
Muslims.
This has been clearly confirmed in many Qur'anic verses and ahadith to the
point where the Shari'ah considered the obedience to the ruler as part of
the obedience to Allah (swt) and His Messenger (saw). Therefore obeying
the ruler entails a reward and disobedience entails punishment.
Following is an evidence from the Qur'an:
"O you who believe! Obey Allah, and obey the Messenger and those of you
who are in authority." [TMQ 4:59]