The Ahlul Bayt are the Godly ones of the Family of the Holy Prophet whom the Muslim World as a whole unanimously acknowledges as the Pure Personalities and hold them as Infallible Holy Ones Purified By God Himself.
“The Almighty Allah has bestowed His trust on Ale Muhammad (The descendants of Muhammad, Peace Be Upon Them), who are the Strongholds of His Commandments. From where they are expounded and interpreted. They are The Fountain Heads of Knowledge Created by Him, Shelters for His Teachings, Forts for Heavenly Books, And lofty Citadels to defend His Religion. Islam needed help and support, By them Allah made Islam strong and powerful.”1
"And We assigned from among them some Imams(Leaders) who guide by Our Authority since they were patient and believed firmly in Our Signs. (Qur'an 32:24)
And, He it is who made the stars for you that ye maybe rightly guided by observing them in the darkness of the land and the sea; Indeed we have made plain the Signs for the people who can know. (Qur'an 6:97).
The Holy Prophet said:
“As the stars in the sky are the Source of guidance to the travellers, The Holy Ones of my Ahlul Bayt ( The Twelve Imams) are The Source of Guidance for the people. And, as the stars will remain in the sky until The Day of Judgment, The earth will never be without a Divinely Guide from My Ahlul Bayt, That is an Imam”.
And say those who disbelieve: "why hath not a sign been sent down unto him(Muhammad); Verily thou art a warner and for every people there is a guide (13:7)
Firmly Ground in Knowledge
"He (God) is He Who Has revealed The Book (Quran) to you. Some of its verses are decisive; they are the Essence of The Book and the others are ambiguous; so as for those in whose hearts there is perversity, they follow the part of it which is ambiguous, seeking to mislead (people) and seeking to give it ( their own) interpretation. But NONE knows its interpretation , Save God and those who are firmly established in Knowledge".(Qur'an 3:7).
"Nay These are The Verses of The Qur'an in the Breast of those who are gifted with Knowledge. (Qur'an: 29:49).
The Blessed Ones
Guide us in the straight path: The path of those whom Thou hast blessed. (1:6&7).
They are those whom Allah has blessed among the Prophets and the truthfuls, and the martyrs and the righteous. (4:69)
These are The Ones on The Guidance from their Lord and these are The Ones shall be The successful ones. (Qur'an: 2:5).
The Purified Ones
Verily It is Qur'an honourable, In a Book hidden, Toucheth It not save the purified ones. Sent down by The Lord of the Worlds. (56:77 to 80).
The Highest degree of purity means to be kept constantly away from all the causes of impurity. This is termed as the State of Infallibility in Knowledge, character and action. It could have been applied generally to the whole mankind who are keeping aloof from all the impurities as The Word of God Commands.
But, God expressively Has confined His Order to certain Group of Individuals by excluding the rest of the mankind from it in His Divine Will by declaring the 'Ahlul Bayt' as the persons purified by Him to be constantly in touch with the Qur'an in its original, hidden, well protected, exalted and purified form. It was Allah's Wish to remove all Blemish from them:
Verily, verily God intendeth to keep off from you (every kind of filth), "O' ye The People of The House (Ahlul Bait), and purify you with a thorough purification. (Qur'an: 33:33).
Commandment to love Ahlul Bayt
In this Last Word of God (Qur'an), The Holy Prophet is being Commanded to ask the believers to love his kith and kin (that is his Ahlul Bayt) and that would be the return of his apostleship.
That is of which God Give the glad tidings unto His servants who believe and do good deeds; Say thou ('O' Apostle Muhammad!) " I demand not of you any recompense for it (the toils of apostleship) save the love of (my) relatives...(42:23).
Ordinance of God
And after returning from City of Mecca after his last or the parting Pilgrimage (Hajjatul Wida’) at a place called Ghadeer Khum this verse was revealed to The Holy Prophet Muhammad, which occupies a very important and a leading position in The Holy Qur'an and forms a very vital part of The Word of God:
"O Apostle! deliver what has been Revealed to you from your Lord, and if you do it not, then you have not delivered His Message, and Allah will protect you from the people, surely Allah will not guide the unbelieving people" (5:67)
Acknowledgement of Ali as the Successor
History reports how the Holy Prophet stopped the caravan, delivered a long sermon, before a mammoth assemble of thousands of the pilgrims and he was standing there to convey the Message to the Muslims and to perform the duty he was ordered to perform. Continuing the sermon, he said:
"O people! Shortly I shall be called (to the Heaven),I am leaving amidst you, two most precious things, worthy of obedience, The Book of Allah (The Holy Qur'an), and 'My Ahlul Bayt' (The members of his family, Ali and Fatima and their Godly offspring), Should ye be attached to these Two, Never shall ye get astray after me, for Verily these TWO will not separate from each other until they meet me at the Fountain of Kauthar (Paradise)."And then he called Ali Ibn Abi Talib and raising him with the miraculous strength of his apostolic arms declared:
'Man kunto Maulaho fa haaza Ali-yun Maulahu'
Whomsoever I am The Maula,(Lord, Master), This Ali is his Maula.
And declared him as The Ameer ul Momeyneen(Commander of the faithful).
Then the Prophet said "Go now, and let those who have been present here today repeat and convey to those who are absent all that they have seen and heard."
Approval of The Religion
And immediately after this historic event, the Divine inspiration again descended revealing:
"This day I perfected for you, your religion, and have completed my favor on you and chosen for you ISLAM (to be ) the Religion", ….(5:3).
Commandment To Believe
Mankind! Verily The Apostle Mohammed hath come unto you with TRUTH from your Lord. Believe then unto him, it is good for you and if you disbelieve then God is whatever is in the Heavens and the Earth and God is All Knowing, All Wise. (4:170).
And We made them Imams (Leaders) by OUR Command and We revealed to them the doing of Good and the keeping up of Prayers and giving of the alms. (And Us)(Alone) did they serve (21:73)
God is He who sent down The Book with Truth and The Balance. What shall make you know , haply the hour (of Reckoning) be nigh (42:17)
"The Two inseparable Associates each one of whom stands as a witness to the truth of the other."
“Since the Ahlul Bayt carry as much weight in the eyes of Allah as The Holy Quran, the former has the same qualities as the latter. Just as the Qur'an is true from beginning to end without the shadow of untruth in it, and just as it is incumbent(duty) of every Muslim to obey its commands, so also must the Ahlul Bayt be perfectly true and sincere guides whose commands must be followed by all. Therefore there can be no escape of accepting their leadership and following their creed and faith. The Muslims are bound by the sayings of prophet to follow them and no one else.”2
Those who have faith in god and do righteous deeds they are the best of creatures (khairul barriya). (98:7)
These are none but our Infallible Imams.
“Peace And The Mercy Of God Be Upon Muhammad And His Descendants.
• Lord Who distinguished Muhammad and His descendants with Excellence
• Entrusted them with Thy mission;
• And favored them with Thy privilege (of intercession);
• Who made them The Heirs to The Prophets;
• Who sealed upon them the succession and Guardianship of the Religion;
• Who taught them The knowledge of all what was and all that remains;
• Who made the hearts for mankind yearn for them.
Lord, Bless Muhammad and his descendants, The Pure Ones, and Do unto us what Thou art Worthy of doing in this world, and the hereafter. Verily Thou Has Power over all things”3
• Nahjul Balagha
• "The Right Path" Translation of: al Muraja't
• Al Sahifah Al Sajjadiyyah.
• Qur'an Mir S.V. Ahmed Ali & M. Shakir &
• Fundamentals of Islam: Agha Mehdi Pooya & Al Kafi