According to the jurists, Sunnah, in its general sense, refers to what the Muslim is rewarded for doing and not punished for giving up. There are confirmed sunnahs and optional ones. Neglecting the confirmed sunnahs, such as the Prayer of the two `Eids, is a sin. As for the optional ones, it is not a sin not to observe them. But one should bear in mind that though one is not blamed for not observing optional sunnahs, yet one should not get accustomed to that. Giving up the optional sunnahs is a serious sign of declining. The way to draw closer to Almighty Allah is to follow the Prophet’s Sunnah in all its aspects.
Allah Almighty says: (Say, (O Muhammad, to mankind): If ye love Allah, follow me; Allah will love you and forgive you your sins. Allah is Forgiving, Merciful.)(Aal `Imran 3:31) He Almighty also says: (Verily in the Messenger of Allah ye have a good example for him who looketh unto Allah and the last Day, and remembereth Allah much.)(Al-Ahzab 33:21). The Prophet (peace and blessings be upon him) said: “Follow my Sunnah and the Sunnah of the Rightly-Guided Caliphs (who would come) after me; Hold fast to them.”
Sheikh Faisal Mawlawi, Deputy Chairman of the European Council for Fatwa and Research, states: According to the science of usul al-fiqh (principles of Islamic jurisprudence), the Sunnah of the Prophet (peace and blessings be upon him) means all that has been reported of the Prophet (peace be upon him) in a certain way, whether the reports are sayings, actions or tacit approvals. The Sunnah in that sense is regarded as the second source of Shari`ah after the Qur’an.
It is through the Sunnah that we can know whether a certain act is obligatory (wajib), forbidden (haram), recommendable (mandub), undesirable (makruh), or permissible (mubah). Abiding by the Sunnah is to put acts in their lawful framework.
Accordingly, if an act is proved to be forbidden, it is not lawful for one to do it, and if one commits it, one will be sinful.
If an act is proved to be obligatory, one is obliged to abide by it, and if one neglects it, one will be sinful.
If an act is proved to be undesirable, it will be better for one not to do it. If one does not do it, one will be rewarded for that, but if one does it, one will not be regarded sinful.
If an act is proved to be recommendable, it will be better for one to do it. If one does it, one will be rewarded for that, but if one does not do it, one will not be regarded sinful.
If an act is proved to be permissible, one is free to do or give it up; either case can be followed.
As for the science of jurisprudence, Sunnah refers to the recommendable acts that the Prophet (peace and blessings be upon him) did but did not enjoin the Muslims to follow. If one does such acts, one will be rewarded, for by doing so, one follows in the footsteps of the Prophet (peace and blessings be upon him); and if one does not do them, one will not be punished, for he (peace and blessings be upon him) did not enjoin them.
There is much evidence on the importance of following the Prophet’s Sunnah. Allah Almighty, for example, says: (Whosoever obeyeth Allah and His Messenger, he verily hath gained a signal victory.)(Al-Ahzab 33:71). He Almighty also says: (Whoso obeyeth Allah and His Messenger, He will make him enter Gardens underneath which rivers flow, where such will dwell for ever. That will be the great success. And whoso disobeyeth Allah and His Messenger and transgresseth His limits, He will make him enter Fire.)(An-Nisaa’ :13-14). He Almighty also says: (And whoso is rebellious to Allah and His Messenger, he verily goeth astray in error manifest.)(Al-Ahzab 33:36) Another verse says: (And whoso disobeyeth Allah and His Messenger, lo! his is fire of hell, wherein such dwell for ever.)(Al-Jinn 72:23)
It is mentioned in the Kuwaiti Encyclopedia of Islamic Jurisprudence that according to the Hanafi School, the legally responsible Muslims are regarded sinful if they neglect the confirmed sunnahs that are considered of the rituals of Islam, such as the congregational Prayers, Adhan (call for Prayer), the Prayer of the two `Eids. Some have attributed this view also to the Shafi`i School. This is because giving up the confirmed sunnahs is a kind of belittling of the Shari`ah.
Hence, if a people of a certain village or city have agreed to give up the confirmed Sunnahs, they are to be fought for that. This is not the case with the optional sunnahs, for they are to be offered individually.