Hearing this...
Hearing this, the Prophet declared: "I am the Master (Mawla) of the faithfuls, and I have rights over them even more than what they have over themselves. Therefore, whoever I am his Mawla, (this) Ali is his Mawla (Master/ Chief)". The Prophet (p.b.u.h.) had already introduced his Ahl-ulBait on several Occasions as "the ship of Noah", "the strong rope of God", "the door of forgiveness", "and the purified ones" and made "their love incumbent upon his followers".
He had similarly, on many occasions, pointed out Ali as "My brother and Successor", "the door of the city of my knowledge", "the most equitable judge", "the embodiment of faith", and having the position with regard to him as "Aron was to Moses".
A renowned historian Ibn Khawand Shah (died 1903) on page 173 of the first volume of his book 'Rawzatus Safa' wrote "When the meeting, held under the serene and blissful atmosphere of the revelation, ended, the Holy Prophet made Imam Ali to sit in a special pitched tent, and ordered the Muslims to proceed, group by group, to congratulate him on his succession. When the men had finished their greetings, the Apostle of Allah ordered the wives to go and offer their congratulations".
According to the narration of Zaid Ibn Arqam, a well-known companion of the Prophet, immediately on receiving the orders of the Prophet the entire crowd with one voice said, "By all means we shall most willingly obey the mandate of God Almighty and His Apostle" and moved towards Imam Ali bin Abi Talib. Omar bin Khattab was the first to Congratulate Hazrat Ali in the following words.
“Bakhin bakhin laka yaibn Abi Taleb asbahta Maulaayee Wa Maula Kullau Momineen wa mominaatin.” "Greetings to you, O son of Abu Taleb! You have dawned as my master and the master of all faithful men and women". He was followed by Abu Bakr, Osman, Talha and Zubair who were among the first to clasp, the hands of Ali and Swear allegiance.
They were followed by the Muhajirs (volunteers), and Ansars (helpers), and then the rest of congregation who swore allegiance to Ali; and congratulated him on his designation as commander of the faithful people. This grand Celebration continued for full three days.