The Sunna, the example of the Prophet, upon him be peace and blessings, is the main source of our religious life, promoted and encouraged by the Koran. To cite a few verses:

It is not for any believer, man or woman, when God and His Messenger have decreed a matter, to have the choice in the affair. Whosoever disobeys God and His Messenger has gone astray into manifest error. (al-Ahzab, 33.36)

...Those who indeed believe in Our signs, those who follow the Messenger, the unlettered Prophet, whom they find written down with them in the Torah and the Gospel, enjoining on them the good, and forbidding them the evil, making lawful for them the good things and making unlawful for them the corrupt things, and relieving them of their loads, and the fetters that were upon them. Those who believe in him and succor him and help him, and follow the light that has been sent down with him – they are the prosperers. (al-A‘raf, 7.156–7)

He Who raised among the unlettered ones a Messenger from them, reciting to them His signs, purifies them and instructs them in the Book and the Wisdom. (al-Jumu‘a, 62.2)

What is meant by the Wisdom in the last verse is, according to most interpreters of the Koran and the Traditionists, the Sunna. the Koran, being of a miraculous exposition, is never otiose nor exceeds the proper terms: as Wisdom in the verse comes after Book as a separate word, it must refer to something different from the Book. the Book is the Koran and the Wisdom is the Sunna which expands on what is brief in the Book and clarifies its ambiguities, specifies what is unconditional and general and vice versa, so that general principles or specific rulings can be understood from what is commanded in the Koran.

The Koran in many verses enjoins absolute obedience to God’s Messengers. This obedience is not due to their person, but because of their mission as the ‘officials’ of God in guiding people to truth both individually and socially, materially, intellectually and spiritually.

We have not sent a Messenger save to be obeyed by God’s leave. (al-Nisa’, 4.64)
O you who believe! Obey God and His Messenger, and do not turn away from him. (al-Anfal, 8.20)

Obedience to God means unconditional obedience to His Commandments in the Koran and His laws in life and in the operation of the universe. Obedience to the Messenger, upon him be peace and blessings, is following his way in all the aspects of life, in practicing the Koran, and in all the orders of the Messenger besides the Koran. the Sunna contains all the orders and prohibitions, warnings and encouragements of God’s Messenger, who said: Take care! I have been given the Book and its like together with it.¹

Verse 20 of al-Anfal warns the Muslims not to turn away from the Messenger. Therefore, disobedience to the Sunna, even belittling and criticizing it, amounts to heresy, even apostasy.

There are many other verses which emphasize the importance of the Sunna, or following the example of God’s Messenger, upon him be peace and blessings:

O you who believe! Obey God and obey the Messenger and those in authority from amongst you. (al-Nisa’, 4.59)

The verse stresses, besides obedience to God, obedience to God’s Messenger, and the repetition of the verb obey in the imperative mood points to the fact that the Messenger has the authority to command or forbid, and that the Muslims must carry out his commands and refrain from his prohibitions. Besides, where obedience to those in authority who share the same faith and feelings as the Muslims, is ordered, the Prophet has a far greater right to be obeyed.

Another verse:

Obey God and His Messenger and do not dispute with one another, lest you should be dissolved (dispersed) and your strength fade away; and be steadfast. (al-Anfal, 8.46)

According to this verse, the strength and unity of the Muslims lie in their submission to God and His Messenger. the Sunna is the unique way or example set by God’s Messenger for the Muslims to follow. Also, it is through the Sunna that a Muslim can live according to the Koran. by putting the Koran into practice, God’s Messenger, upon him be peace and blessings, established the way which the Muslims must follow. From this viewpoint, the Sunna is more comprehensive than the Koran and, without it, the Muslims cannot design their life according to the Koran. So, obedience to God is possible by obeying the Messenger or by following his Sunna. This is explicitly stated in the following verse:

Say (O Muhammad!): ‘If you love God, follow me so that God loves you.’ (Al ‘Imran, 3.31)

Love of God is impossible for one to acquire without following the Prophet, upon him be peace and blessings. No one can claim love of God, nor can he be loved by God, unless he follows the Sunna.

Another verse:

Surely there is for you in God’s Messenger an excellent example for him who aspires to God and the Hereafter, and mentions God oft. (al-Ahzab, 33.21)

In order to secure himself against any deviation and to follow the Straight Path without going astray, a Muslim must cling to the Sunna of the Prophet, upon him be peace and blessings.

One day a woman came to ‘Abdullah ibn Mas‘ud and said: ‘I have heard that you call down God’s curse upon the women who have tattoos on their bodies, who pluck hairs on their faces, who force their teeth apart in order to look more beautiful, and who change the creation of God.’ Ibn Mas‘ud answered: ‘This is to be found in the Scripture of God.’ the woman objected: ‘I swear by God that I have read whatever is between the two covers of the Book but could not find anything in it related to this matter,’ Ibn Mas‘ud concluded: ‘Our Prophet called God’s curse upon the women who wear wigs, who join somebody’s hair to theirs, and who have tattoos on their bodies. And, have you not read in the Koran: Whatever the Messenger brings to you, adopt it, and whatever he forbids you, refrain from it (al-Hashr, 59.7)?’²

The Koran also declares:

Nay, by your Lord, they will never become believers until they choose you as judge to settle the matters in dispute between them. (al-Nisa’, 4.65)