Allah, the Exalted, says:

"And whatsoever the Messenger (Muhammad (PBUH)) gives you, take it; and whatsoever he forbids you, abstain (from it)". (59:7)

"Nor does he speak of (his own) desire. It is only a Revelation that is revealed.'' (53:3,4)

"Say (O Muhammad (PBUH) to mankind): `If you (really) love Allah then follow me (i.e., accept Islamic Monotheism, follow the Qur'an and the Sunnah), Allah will love you and forgive you of your sins". (3:31)

"Indeed in the Messenger of Allah (Muhammad (PBUH)) you have a good example to follow for him who hopes for (the Meeting with) Allah and the Last Day...'' (33:21)

"But no, by your Rubb, they can have no Faith, until they make you (O Muhammad (PBUH)) judge in all disputes between them, and find in themselves no resistance against your decisions, and accept (them) with full submission". (4:65)

"(And) if you differ in anything amongst yourselves, refer it to Allah and His Messenger (PBUH)". (4:59)

"He who obeys the Messenger (Muhammad (PBUH)), has indeed obeyed Allah.'' (4:80)

"And verily, you (O Muhammad (PBUH)) are indeed guiding (mankind) to the Straight Path (i.e., Allah's Deen of Islamic Monotheism):. (42:52)

"And let those who oppose the Messenger's (Muhammad (PBUH)) commandment (i.e., his Sunnah -- legal ways, orders, acts of worship, statements) (among the sects), beware, lest some Fitnah (disbelief, trials, afflictions, earthquakes, killing, overpowered by a tyrant) should befall them or a painful torment be inflicted on them.'' (24:63)

"And remember (O you the members of the Prophet's family, the Graces of your Rubb), that which is recited in your houses of the Verses of Allah and Al-Hikmah (i.e., Prophet's Sunnah -- legal ways, so give your thanks to Allah and glorify His Praises for this Qur'an and the Sunnah).'' (33:34)