Imam Sadiq (peace be upon him): Mufaddal narrates: A letter was written to Imam Sadiq (peace be upon him), and this is his reply: "Allah has appointed the lawful and the unlawful as lawful and unlawful until the Day of Judgement, and recognition of the messengers, acceptance of their wilayah (guardianship), and obedience to them is among the lawful [and obligatory] things. The lawful is what they deem permissible, and the unlawful is what they deem forbidden; they are the fundamental roots, and from them the branch of the lawful comes into being. This is their endeavour, and one of their duties is that they command their followers and the people of their wilayah to lawful deeds… The enemies of the Prophet are the very unlawful things, and their followers, until the Day of Judgement, are the indecencies and the reprehensible deeds, both hidden and manifest, and wine, gambling, fornication, usury, blood, carrion, and the flesh of swine. They are the real unlawful and the root of every unlawful thing… Take note that if I said that prayer, zakat, the fast of the month of Ramadan, Hajj, Umrah, the Masjid al-Haram, the House of Allah, the Mash'ar al-Haram, purification, the ritual bath from janabah, and every obligation is the Prophet (peace be upon him and his family) who brought these commands from Allah, I would have spoken the truth; because all these commands are known through the Prophet (peace be upon him and his family). If it were not for the recognition of the Prophet, faith in him, and submission to his command, these commands would not be known. This is a bounty from Allah upon those who possess such a blessing. So all of these, in root and branch, are the Prophet (peace be upon him and his family). He called me to this religion, guided me, made me recognise it, commanded me with these instructions, and made obedience obligatory upon me, so that recognising him became necessary for me. How is it possible that I do not recognise the one who is the intermediary between me and Allah? How can I say that religion is other than the Prophet (peace be upon him and his family), when he brought religion for me from Allah? And how is this not the recognition of the person himself, when that very person brought the religion from Allah? The one who denies religion is the one who denies the Prophet (peace be upon him and his family). They said: 'Has Allah sent a human being as messenger?' (Isra/94). Allah wishes to be recognised through [certain] men, and that through following them His obedience be carried out, and He has made the path of those men His own path. He accepts nothing else from anyone; He cannot be called to account, but people are called to account. Allah in this verse [expresses] His love for the following of the prophets: مَنْ یُطِعِ الرَّسُولَ فَقَدْ أَطاعَ اللهَ وَ مَنْ تَوَلَّی فَما أَرْسَلْناکَ عَلَیْهِمْ حَفِیظاً [Whoever obeys the Apostle, he indeed obeys Allah, and whoever turns back, so We have not sent you as a keeper over them]. One who believes that all these obligations are [in essence] a person, and understands what is meant by this statement, has spoken the truth. But one who says this without following the commands, clinging to the root while abandoning the branches, has erred and gains no benefit — just as bearing witness to لَا إِلَهَ إِلَّا اللهُ [there is no god but Allah] alone, without bearing witness to the messengership of Muhammad al-Mustafa (peace be upon him and his family), is not sufficient. Allah [sent] every prophet commanded with good deeds, justice, praiseworthy character, virtuous actions, and forbidding indecencies both hidden and manifest. The hidden indecencies are the acceptance of the wilayah of the oppressive leaders, and the manifest indecencies are the branches of that wilayah and following it."