Imam Sadiq (peace be upon him): Mufaddal ibn Umar al-Ju'fi said: I asked my master Imam Sadiq (peace be upon him) about this saying of Allah the Mighty and Majestic: قُلْ فَلِلّهِ الحُجَّةُ الْبَالِغَةُ فَلَوْ شَاءَ لَهَدَاکُمْ أَجْمَعِینَ [Say: Then Allah's is the conclusive argument; so if He please, He would certainly guide you all]; and Imam Sadiq (peace be upon him) said: "الْحُجَّةُ الْبَالِغَةُ [the conclusive argument] means the argument that reaches the ignorant among the People of the Book, and they come to know it through their ignorance just as the scholar knows it through his knowledge, because Allah the Mighty and Majestic is more noble and more just than to punish anyone without a proof." Then Imam Sadiq (peace be upon him) recited this verse: "It was not for Allah that He should lead a people astray after He had guided them [and they had believed], until He makes clear to them what they should guard against." (Tawbah/115) Then the Imam (peace be upon him) began to narrate this hadith: The Messenger of Allah (peace be upon him and his family) did not pass away except after the completion of the religion, the perfection of the blessing, and the pleasure of the Lord, and Allah revealed this verse to His Prophet (peace be upon him and his family) in the region of Kura' al-Ghamim: "O Messenger! Convey fully [to the people] what has been sent down to you from your Lord! And if you do not, you will not have conveyed His message!" (Ma'idah/67). Because the Messenger of Allah (peace be upon him and his family) feared the apostasy of the hypocrites who concealed enmity toward Ali (peace be upon him). When the Prophet (peace be upon him and his family) reached Ghadir Khumm after the completion of Hajjat al-Wada' (the Farewell Pilgrimage), he began to deliver a sermon to the Muhajirin and Ansar, and after praising Allah he addressed them saying: "O company of Muhajirin and Ansar! Am I not more entitled to you than you are to yourselves?" They said: "By Allah, yes." The Messenger of Allah (peace be upon him and his family) said three times: "O Allah, You Yourself be the witness." Then he said: "O Ali (peace be upon him)!" Ali (peace be upon him) answered: "At your service, O Messenger of Allah (peace be upon him and his family)!" He said: "Stand up! For indeed Allah has commanded me to convey His message and messages concerning you, and Jibra'il has brought it down from Allah: 'O Messenger! Convey fully [to the people] what has been sent down to you from your Lord! And if you do not, you will not have conveyed His message!' (Ma'idah/67)" So Ali (peace be upon him) stood up, and the Messenger of Allah (peace be upon him and his family) took his hand and raised his arm until the people saw the whiteness under his armpit. Then he said: "Whoever's mawla (master) I am, Ali (peace be upon him) is also his mawla. O Allah, love whoever loves him and be an enemy to whoever is his enemy, help whoever helps him, and forsake whoever forsakes him." Umar ibn al-Khattab was the first from the Muhajirin and Ansar to stand up, and he said: "Congratulations to you, O Ali (peace be upon him)! You have become my mawla and the mawla of every believing man and woman." Then Jibra'il descended and brought this verse: "Today I have perfected your religion for you and completed My blessing upon you and have approved Islam as [the everlasting] religion for you." (Ma'idah/2) Therefore, on this day, Allah the Exalted, through Ali (peace be upon him), perfected His religion for you, O Muhajirin and Ansar, completed His blessing upon you, and approved Islam as your religion. So listen to him and obey him, that you may attain salvation.