The Prophet (Sallallahu ‘Alaihi Wa Sallam) sent for the two boys who owned the date-store and asked them to name the price of the yard. They answered, “Nay, but we shall make thee a gift of it, O Prophet of Allah!” The Prophet (Sallallahu ‘Alaihi Wa Sallam), however, refused their offer, paid them its price and built a mosque from there. (39)
The Prophet (Sallallahu ‘Alaihi Wa Sallam) himself carried the unburned bricks for construction of the building along with the other Muslims. He is reported to have recited as he worked.
“O Allah! The true reward is the reward of the hereafter, have mercy O Allah on the Ansaars and Mujajirun.” (Ibn Kathir, Vol. II, p. 251)
Overjoyed to see the Messenger of Allah (Sallallahu ‘Alaihi Wa Sallam) invoking blessings on them, the Muslims, too, sang and thanked Allah.
The Prophet (Sallallahu ‘Alaihi Wa Sallam) lived in the house of Abu Ayyub Ansaari for seven months. (Ibn Kathir, Vol. II, p. 279)
In the meantime, the construction of the mosque and dwelling place for the Prophet’s family (radiallahu ‘anhum) was already completed and so he moved to live in his house.
The Muslims who had been restrained from migration by the polytheist of Makkah, continued to emigrate to Madinah until the only ones left there were those who were either forcibly detained or had apostatized. On the other hand, not a house of Ansaar was left without the people having sworn allegiance to Allah and His Prophet (Sallallahu ‘Alaihi Wa Sallam). (Ibn Hisham, Vol. I, pp. 499-500).
BONDS OF BROTHERHOOD BETWEEN THE ANSAARS AND MUHAAJIRUN
The Prophet (Sallallahu ‘Alaihi Wa Sallam) established bonds of brotherhood between the Muhaajirun and the Ansaar putting them under an agreement and obligation to mutual welfare, benevolence and assistance. Each Ansaari took a Muhaajir brother where the former went so far as to give his Muhaajir brother half of whatever he possessed in the form of houses, assets, lands and groves. Such was the enthusiasm of the Ansaars to share everything with their brothers-in-faith that they divided everything into two parts to draw lots for allocating their share. In most cases, they tried to give the Muhaajirun the fairer portion of their property.
An Ansaari would say to his émigrant brother “Behold, I shall divide my possessions into two halves. And I have two wives, thou see whichever of the two pleaseth thee better, and tell me her name. I shall divorce her and thou wed her.” The Muhaajir would answer, “Bless thee Allah in thy family and thy possession! Just tell me, where is the market?”
The Ansaar were magnanimous and self-denying and the Muhaajir forbearing, self-reliant.”(40)
COVENANT BETWEEN THE MUSLIMS AND THE JEWS
Shortly thereafter, the Prophet (Sallallahu ‘Alaihi Wa Sallam) got a written document, which bound the Muhaajirun and the Ansaars to a friendly agreement. The covenant made the Jews a party to the treaty that guarantees them the freedom of their rights and obligations. (Ibn Hisham, Vol. p. 501)
FOR MORE DETAILS OF THE TREATIE CLICK HEAR
THE CALL TO PRAYER
After the Prophet (Sallallahu ‘Alaihi Wa Sallam) had settled down and Islam was deeply entrenched in the soil of Madinah, the mode of calling the faithful to prayer caught the attention of the Prophet (Sallallahu ‘Alaihi Wa Sallam). He disliked the customs of the Jews and Christians such as kindling fire or the use of bell and horn to summon the people to such a spiritual obligation. Initially, the Muslims used to come by themselves for prayer at the scheduled time without any announcement or call at all. While different proposals were being considered, Allah guided the Muslims to the method of giving the call to prayer. A number of companions had a vision of the call in their dreams, which was approved by the Prophet (Sallallahu ‘Alaihi Wa Sallam) and prescribed as the official procedure of assembling the Muslims for such a worship act. Bilal Ibn Rabah (radiallahu ‘anhu) was entrusted by the Prophet (Sallallahu ‘Alaihi Wa Sallam) to give the call to prayer and thus he came to be known as the muadhin of the Prophet (Sallallahu ‘Alaihi Wa Sallam) and the leader of all those who would call the faithful to prayer ‘till the end of time.
 Bukhari, Chapter Arrival of the Prophet and his companions in Medina.
 Bukhari, see the conversation between ‘Abdur Rahan b. Auf and S’ad b. Rabi in the section dealing with the Brotherhood established by the Prophet between the Muhajirin and the Ansar.