"As stipulated in the partnership agreement (Quran) between Allah and Muhammad, Muslims are required to obey and to believe in both Muhammad and Allah.
Quran 4:59 YUSUFALI: O ye who believe! Obey Allah, and obey the Messenger, and those charged with authority among you. If ye differ in anything among yourselves, refer it to Allah and His Messenger, if ye do believe in Allah and the Last Day: That is best, and most suitable for final determination
Quran 7:158 YUSUFALI: Say: "O men! I am sent unto you all, as the Messenger of Allah, to Whom belongeth the dominion of the heavens and the earth: there is no god but He: it is He That giveth both life and death. So believe in Allah and His Messenger, the Unlettered Prophet, who believeth in Allah and His words: follow him that (so) ye may be guided."
Quran 8:1 YUSUFALI: They ask thee concerning (things taken as) spoils of war. Say: "(such) spoils are at the disposal of Allah and the Messenger: So fear Allah, and keep straight the relations between yourselves: Obey Allah and His Messenger, if ye do believe."
Quran 24:47 YUSUFALI: They say, "We believe in Allah and in the messenger, and we obey": but even after that, some of them turn away: they are not (really) Believers.
Quran 47.33 YUSUFALI: O ye who believe! Obey Allah, and obey the messenger, and make not vain your deeds!
Quran 48.9 YUSUFALI: In order that ye (O men) may believe in Allah and His Messenger, that ye may assist and honour Him, and celebrate His praise morning and evening.
Quran 57.7 YUSUFALI: Believe in Allah and His messenger, and spend (in charity) out of the (substance) whereof He has made you heirs. For, those of you who believe and spend (in charity),- for them is a great Reward.
Quran 61:11 YUSUFALI: That ye believe in Allah and His Messenger, and that ye strive (your utmost) in the Cause of Allah, with your property and your persons: That will be best for you, if ye but knew!
Quran 64:8 YUSUFALI: Believe, therefore, in Allah and His Messenger, and in the Light which we have sent down. And Allah is well acquainted with all that ye do."
http://wikiislam.net/wiki/Farsideology:_Condition_of_Partnership