The promise of Allah
The promise made by Allah (SWT) in Qur'an 15:9 is obviously fulfilled in the undisputed purity of the Qur'anic text throughout the fourteen centuries since its revelation. However, what is often forgotten by many Muslims is that the divine promise also includes, by necessity, the Sunnah of the Prophet (PBUH), because the Sunnah is the practical example of the implementation of the Qur'anic guidance, the wisdom taught to the Prophet (PBUH) along with the scripture, and neither the Qur'an nor the Sunnah can be understood correctly without the other.
Allah (SWT) preserved the Sunnah by enabling the companions and those after them to memorize, write down and pass on the statements of the Prophet (PBUH), and the descriptions of his way, as well as to continue the blessings of practicing the Sunnah.
Prophet Muhammed[saw]true follower of Allah:
48: 29. Muhammad (SAW) is the Messenger of Allâh…………..
4: 64. We sent no Messenger, but to be obeyed by Allâh's Leave.
13: 37. And thus have We sent it (the Qur'ân) down to be a judgement of authority in Arabic. Were you (O Muhammad SAW) to follow their (vain) desires after the knowledge which has come to you, then you will not have any Walî (protector) or defender against Allâh.
13: 38. And indeed We sent Messengers before you (O Muhammad SAW), and made for them wives and offspring. And it was not for a Messenger to bring a sign except by Allâh's Leave. (For) each and every matter there is a Decree (from Allâh).
33: 21. Indeed in the Messenger of Allâh (Muhammad SAW) you have a good example to follow for him who hopes in (the Meeting with) Allâh and the Last Day and remembers Allâh much.
42: 24. Or say they: "He has invented a lie against Allâh?" If Allâh willed, He could have sealed your heart (so that you forget all that you know of the Qur'an). And Allâh wipes out falsehood, and establishes the truth (Islâm) by His Word (this Qur'an). Verily, He knows well what (the secrets) are in the breasts (of mankind).
42:51. . It is not given to any human being that Allâh should speak to him unless (it be) by Inspiration, or from behind a veil, or (that) He sends a Messenger to reveal what He wills by His Leave. Verily, He is Most High, Most Wise .
52. And thus We have sent to you (O Muhammad SAW) Ruhan (an Inspiration, and a Mercy) of Our Command. You knew not what is the Book, nor what is Faith? But We have made it (this Qur'ân) a light wherewith We guide whosoever of Our slaves We will. And verily, you (O Muhammad SAW) are indeed guiding (mankind) to the Straight Path (i.e. Allâh's religion of Islâmic Monotheism).
43: 43. So hold you (O Muhammad SAW) fast to that which is inspired in you. Verily, you are on a Straight Path.
45: 18. Then We have put you (O Muhammad SAW) on a plain way of (Our) commandment [like the one which We commanded Our Messengers before you (i.e. legal ways and laws of the Islâmic Monotheism)]. So follow you that (Islâmic Monotheism and its laws), and follow not the desires of those who know not
46: 8. Or say they: "He (Muhammad SAW) has fabricated it." Say: "If I have fabricated it, still you have no power to support me against Allâh. He knows best of what you say among yourselves concerning it (i.e. this Qur'ân)! Sufficient is He for a witness between me and you! And He is the Oft-Forgiving, the Most Merciful."
48: 8. Verily, We have sent you (O Muhammad SAW) as a witness, as a bearer of glad tidings, and as a warner.
9. In order that you (O mankind) may believe in Allâh and His Messenger (SAW), and that you assist and honour him (SAW), and (that you) glorify (Allâh's) praises morning and afternoon.
sunna of prophet:
62: 2. He it is Who sent among the unlettered ones a Messenger (Muhammad SAW) from among themselves, reciting to them His Verses, purifying them (from the filth of disbelief and polytheism), and teaching them the Book (this Qur'ân, Islâmic laws and Islâmic jurisprudence) and Al-Hikmah (As-Sunnah: legal ways, orders, acts of worship, etc. of Prophet Muhammad SAW). And verily, they had been before in mainfest error;
Quran and Sunna strength of believer:
Bukhari :: Book 9 :: Volume 92 :: Hadith 381
9: 63. Know they not that whoever opposes and shows hostility to Allâh (ÚÒ æ Ìá) and His Messenger (SAW), certainly for him will be the Fire of Hell to abide therein. That is extreme disgrace.
24: ……..And let those who oppose the Messenger's (Muhammad SAW) commandment (i.e. his Sunnah legal ways, orders, acts of worship, statements, etc.) (among the sects) beware, lest some Fitnah (disbelief, trials, afflictions, earthquakes, killing, overpowered by a tyrant, etc.) befall them or a painful torment be inflicted on them.
33: 71. He will direct you to do righteous good deeds and will forgive you your sins. And whosoever obeys Allâh and His Messenger (SAW) he has indeed achieved a great achievement (i.e. he will be saved from the Hell-fire and made to enter Paradise).
49: 7. And know that, among you there is the Messenger of Allâh (SAW). If he were to obey you (i.e. follow your opinions and desires) in much of the matter, you would surely be in trouble, but Allâh has endeared the Faith to you and has beautified it in your hearts, and has made disbelief, wickedness and disobedience (to Allâh and His Messenger SAW) hateful to you. These! They are the rightly guided ones,
61:11. That you believe in Allâh and His Messenger (Muhammad SAW), and that you strive hard and fight in the Cause of Allâh with your wealth and your lives, that will be better for you, if you but know!
72: 23. "(Mine is) but conveyance (of the truth) from Allâh and His Messages (of Islâmic Monotheism), and whosoever disobeys Allâh and His Messenger, then verily, for him is the Fire of Hell, he shall dwell therein forever ."
108: 1. Verily, We have granted you (O Muhammad (Peace be upon him)) Al-Kauthar (a river in Paradise);
3. For he who makes you angry (O Muhammad (Peace be upon him)), - he will be cut off (from every good thing in this world and in the Hereafter).
Muslim :: Book 17 : Hadith 4238
Ubida b. as-Samit repnrted: I was one of those headmen who swore allegiance to Allah's Messenger (may peace be upon him) that we will not associate anything with Allah, and will not commit adultery, and will not steal, and will not kill any soul which Allah has forbidden, but with justice nor plunder, nor disobey (Allah and His Apostle), then Paradise (will be the reward) in case we do these (acts) ; and if we commit any outrage(bad, violence) (and that goes unpunished in the world), it is Allah Who would decide about it. Ibn Rumh said: Its judgment lies with Allah.
Bukhari :: Book 9 :: Volume 93 :: Hadith 560
Narrated 'Ubada bin As-Samit:
I, along with a group of people, gave the pledge of allegiance to Allah's Apostle. He said, "I take your Pledge on the condition that you (1) will not join partners in worship with Allah, (2) will not steal, (3) will not commit illegal sexual intercourse, (4) will not kill your offspring, (5) will not slander, (6) and will not disobey me when I order you to do good. Whoever among you will abide by his pledge, his reward will be with Allah, and whoever commits any of those sins and receives the punishment in this world, that punishment will be an expiation for his sins and purification; but if Allah screens him, then it will be up to Allah to punish him if He will or excuse Him, if He will."
Muslim :: Book 30 : Hadith 5818
Muslim :: Book 24 : Hadith 5301
Muslim :: Book 20 : Hadith 4518
Bukhari :: Book 9 :: Volume 92 :: Hadith 387