Hijrah of Prophet from Makkah to Madinah
Question

I would like some of the brothers to help me find some sources or kind of information about the Hijrah of the Prophet (peace and blessings of Allah be upon him) , because I am doing a research paper on it.
Praise be to Allah.Why did the Prophet migrate to Madinah?
When the persecution of the people of Makkah against the Muslims grew intense, Allah commanded them to migrate so that they could establish the religion of Allah in a land where they could worship Him. 
Allah chose Madinah as the land of hijrah (migration for the sake of Allah). The Messenger (peace and blessings of Allah be upon him) saw in a dream that he was migrating to that city. 
Abu Musa narrated that the Prophet (peace and blessings of Allah be upon him) said: “I saw in a dream that I was migrating from Makkah to a land in which there are date-palms, and I thought that it was al-Yamamah or Hajar, but it turned out to be al-Madinah, Yathrib…” (Narrated by al-Bukhari, 3352; Muslim, 4217) 
Al-Bukhari (3906) narrated that ‘Aishah said: The Prophet (peace and blessings of Allah be upon him) said to the Muslims, “I have been shown the land to which you will migrate: it has palm trees between the two lava fields, the two stony tracts.” So, some people migrated to Madinah , and most of those people who had previously migrated to the land of Ethiopia, returned to Madinah.  
Al-Hafiz said: 
The harrah (stony tract) is land whose stones are black. This dream was different from the dream mentioned above in the hadith of Abu Musa in which the Prophet (peace and blessings of Allah be upon him) was not sure where that land was. Ibn al-Tin said: The Prophet (peace and blessings of Allah be upon him) was shown the land of migration in a way that could apply to Madinah and to other places, then he was shown the feature that is unique to Madinah so it became clear which land that was. 
Who were the first Companions who migrated to Madinah?
With regard to the first Companions of the Prophet (peace and blessings of Allah be upon him) to migrate: 
Al-Bara (may Allah be pleased with him) said: The first ones who came to us of the Companions of the Prophet (peace and blessings of Allah be upon him) were Mus’ab ibn ‘Umayr and Ibn Umm Maktum. They started to teach us the Quran. Then ‘Ammar, Bilal, and Sa’d came, then ‘Umar ibn al-Khattab came with twenty others. Then the Prophet (peace and blessings of Allah be upon him) came, and I never saw the people of Madinah rejoice more than that. They rejoiced so much that I saw the girls and boys saying, “This is the Messenger of Allah (peace and blessings of Allah be upon him), he has come.” (Narrated by al-Bukhari, 4560) 
Hijrah events
The following hadith sums up many of the events of the Prophet’s migration : 
 ‘Aishah said: The Prophet (peace and blessings of Allah be upon him) said to the Muslims:  
“In a dream I have been shown your place of migration, a land of date palm trees, between two lava fields, the two stony tracts.” So, some people migrated to Madinah, and most of those people who had previously migrated to the land of Ethiopia, returned to Madinah. Abu Bakr also prepared to leave for Madinah, but the Messenger of Allah (peace and blessings of Allah be upon him) said to him, “Wait for a while, because I hope that I will be allowed to migrate also.” Abu Bakr said, “Do you indeed expect this? May my father be sacrificed for you!” The Prophet said, "Yes." So Abu Bakr stayed behind for the sake of the Messenger of Allah (peace and blessings of Allah be upon him) so that he could accompany him. He fed two she-camels he owned with the leaves of the samur tree for four months. 
One day, while we were sitting in Abu Bakr's house at noon, someone said to Abu Bakr, "This is the Messenger of Allah (peace and blessings of Allah be upon him) with his head covered, coming at a time at which he never used to visit us before." Abu Bakr said, "May my father and mother be sacrificed for him. By Allah, he has not come at this hour except for something important." So the Messenger of Allah (peace and blessings of Allah be upon him) came and asked permission to enter, and he was admitted. When he entered, he said to Abu Bakr. "Tell everyone who is present with you to go away." Abu Bakr replied, "There is no one here but your family. May my father be sacrificed for you, O Messenger of Allah!" The Prophet said, "I have been given permission to migrate." Abu Bakr said, "Shall I accompany you? May my father be sacrificed for you, O Messenger of Allah!" The Messenger of Allah (peace and blessings of Allah be upon him) said, "Yes." Abu Bakr said, "O Messenger of Allah, may my father be sacrificed for you, take one of these two she-camels of mine." The Messenger of Allah (peace and blessings of Allah be upon him) replied, "(I will accept it) with payment." So we prepared the baggage quickly and put some journey food in a leather bag for them. Asma, the daughter of Abu Bakr, cut a piece from her waist belt and tied the mouth of the leather bag with it, and for that reason she was named Dhat-un-Nitaqayn (i.e. the owner of two belts). 
Then the Messenger of Allah (peace and blessings of Allah be upon him) and Abu Bakr reached a cave on the mountain of Thawr and stayed there for three nights. 
'Abdullah bin Abi Bakr who was an intelligent and wise youth, stayed (with them) overnight. He would leave them before daybreak so that in the morning he would be with Quraysh, as if he had spent the night in Makkah. He would keep in mind any plot made against them, and when it became dark he would (go and) inform them of it. 'Amir bin Fuhayrah, the freed slave of Abu Bakr, used to bring the milch sheep (of his master, Abu Bakr) to them a little while after nightfall. So they always had fresh milk at night, the milk of their sheep. 'Amir bin Fuhayrah would then take the flock away when it was still dark (before daybreak). He did the same on each of those three nights. The Messenger of Allah (peace and blessings of Allah be upon him) and Abu Bakr had hired a man from the tribe of Bani al-Dayl from the family of Bani ‘Abd ibn ‘Adiyy as an expert guide, … he was of the religion of the infidels of Quraysh but the Prophet and Abu Bakr trusted him and gave him their two she-camels and made an appointment with him for him to bring their two she-camels to the cave of the mountain of Thawr in the morning after three nights had passed. And (when they set out), 'Amir bin Fuhayrah and the guide went along with them and the guide led them along the coast. 
Ibn Shihab said: ‘Abd al-Rahman ibn Malik al-Mudliji, who was the nephew of Suraqah ibn Malik ibn Ju'sham, told me that his father informed him that he heard Suraqah ibn Ju'sham saying, "The messengers of the kuffar of Quraysh came to us declaring that they had assigned for the persons who would kill or arrest the Messenger of Allah (peace and blessings of Allah be upon him) and Abu Bakr, a reward equal to their blood money. While I was sitting in one of the gatherings of my tribe, Bani Mudlij, a man from them came to us and stood while we were sitting, and said, 'O Suraqah! No doubt, I have just seen some people far away on the shore, and I think they are Muhammad and his companions.' " Suraqah added, "I too realized that it must have been they. But I said 'No, it is not they, but you have seen so-and-so, and so-and-so whom we saw setting out.' I stayed in the gathering for a while and then got up and left for my home. I ordered my slave-girl to get my horse which was behind a hillock, and keep it ready for me. 
Then I took my spear and left by the back door of my house dragging the lower end of the spear on the ground and keeping it low. Then I reached my horse, mounted it and made it gallop. When I approached them (i.e. Muhammad and Abu Bakr), my horse stumbled and I fell down from it, Then I stood up, got hold of my quiver and took out the divining arrows and drew lots as to whether I should harm them (i.e. the Prophet and Abu Bakr) or not, and the lot which I disliked came out. But I remounted my horse and let it gallop, giving no importance to the divining arrows. When I heard the recitation of the Quran by the Messenger of Allah (peace and blessings of Allah be upon him) who was not looking around although Abu Bakr kept doing that, suddenly the forelegs of my horse sank into the ground up to the knees, and I fell down from it. Then I rebuked it and it got up but it could hardly lift its forelegs from the ground, and when it stood up straight again, its forelegs caused dust to rise up in the sky like smoke. Then again I drew lots with the divining arrows, and the lot which I disliked, came out. So I called to them to let them know they were safe. They stopped, and I remounted my horse and went to them. When I saw how I had been hampered from harming them, it came to my mind that the Cause of the Messenger of Allah (peace and blessings of Allah be upon him) (i.e. Islam) would become victorious. So I said to him, "Your people have assigned a reward equal to the blood money for your capture." Then I told them all the plans the people of Makkah had made concerning them. Then I offered them some journey food and goods but they refused to take anything and did not ask for anything, but the Prophet (peace and blessings of Allah be upon him) said, "Do not tell others about us." Then I requested him to write for me a guarantee of security. He ordered 'Amir bin Fuhayrah to write it for me on a piece of animal skin, then the Messenger of Allah (peace and blessings of Allah be upon him) went on his way." 
Ibn Shihab said: 'Urwah ibn al-Zubayr told me: The Messenger of Allah (peace and blessings of Allah be upon him) met al-Zubayr in a caravan of Muslim merchants who were returning from Syria. Al-Zubayr gave the Messenger of Allah (peace and blessings of Allah be upon him) and Abu Bakr a gift of white clothes. When the Muslims of Madinah heard the news of the departure of the Messenger of Allah (peace and blessings of Allah be upon him) from Makkah (towards Madinah), they started going to the harrah (lava field) every morning. They would wait for him till the heat of the noon forced them to return. One day, after waiting for a long while, they returned home, and when they went into their houses, a Jew climbed up onto the roof of one of the forts of his people to look for something, and he saw the Messenger of Allah (peace and blessings of Allah be upon him) and his companions dressed in white clothes, as if they were emerging out of a desert mirage. 
The Jew could not help shouting at the top of his voice, "O Arabs! Here is your great man whom you have been waiting for!" So all the Muslims rushed to pick up their weapons and went to meet the Messenger of Allah (peace and blessings of Allah be upon him) on the lava field. The Prophet turned with them to the right and alighted in the land of Bani 'Amr ibn 'Awf. This was on Monday in the month of Rabee’ al-Awwal. Abu Bakr stood up, receiving the people while the Messenger of Allah (peace and blessings of Allah be upon him) sat down and kept silent. Some of the Ansar who came and had not seen the Messenger of Allah (peace and blessings of Allah be upon him) before, began greeting Abu Bakr, but when the sunshine fell on the Messenger of Allah (peace and blessings of Allah be upon him) and Abu Bakr came forward and shaded him with his cloak, only then did the people come to know the Messenger of Allah (peace and blessings of Allah be upon him).  
The Messenger of Allah (peace and blessings of Allah be upon him) stayed with Bani 'Amr ibn 'Awf for ten nights and established the mosque (mosque of Quba) which was founded on piety. The Messenger of Allah (peace and blessings of Allah be upon him) prayed in it and then mounted his she-camel and moved on, accompanied by the people till his she-camel knelt down at (the place of) the mosque of the Messenger of Allah (peace and blessings of Allah be upon him) at Madinah. Some Muslims used to pray there in those days, and that place was a yard for drying dates belonging to Suhayl and Sahl, two orphan boys who were under the guardianship of As’ad ibn Zurarah. When his she-camel knelt down, the Messenger of Allah (peace and blessings of Allah be upon him) said, "This place, Allah willing, will be our place." The Messenger of Allah (peace and blessings of Allah be upon him) then called the two boys and told them to name a price for that yard so that he might take it as a mosque. The two boys said, "No, but we will give it as a gift, O Messenger of Allah!" The Messenger of Allah (peace and blessings of Allah be upon him) refused to take it as a gift and insisted on buying it from them, then he built a mosque there. The Prophet himself started carrying unburnt bricks for its building and while doing so, he was saying "This load is better than the load of Khaybar, for it is more pious in the Sight of Allah and purer and better rewardable."
He was also saying, "O Allah! The actual reward is the reward in the Hereafter, so bestow Your Mercy on the Ansar and the Muhajirin."
Thus the Prophet recited (by way of proverb) the poem of some Muslim poet whose name is unknown to me. 
Ibn Shibab said, "We have not heard in any ahadith that the Messenger of Allah (peace and blessings of Allah be upon him) recited any complete line of poetry apart from this.” (Narrated by al-Bukhari, 3906)
Misconceptions about hijrah
But there is a specious argument put forward by some of those who want to stir up doubts about Islam. They say that the sirah narrated that the Messenger (peace and blessings of Allah be upon him) and Abu Bakr migrated with two she-camels, and they entered the cave, and Quraysh pursued them; if they had two she-camels with them, the people of Quraysh would have known that Muhammad (peace and blessings of Allah be upon him) and his Companion had entered the cave. So where were the two camels? 
These doubters want to attack Islam so that people will not believe the sirah of the Messenger (peace and blessings of Allah be upon him), and to make them think that the sirah is based on illusions and lies.  
The response to this specious argument is very simple indeed. The report quoted above – of which these people are unaware, or they ignore it – tells them that the Messenger (peace and blessings of Allah be upon him) had hired a guide to show them the way, and even though he was a follower of the kafir religion of Quraysh, they trusted him. So they gave their mounts to him and made an appointment with him for him to bring their mounts back to them at the cave of Thawr after three nights had passed. 
This hadith clearly refutes their specious argument and shuts them up. Praise be to Allah for guidance after misguidance. 
Another thing that happened to the Messenger of Allah (peace and blessings of Allah be upon him) and Abu Bakr on their way to Madinah: 
Abu Bakr (may Allah be pleased with him) said: I said to the Prophet (peace and blessings of Allah be upon him) – when I was in the cave – “If any one of them looks down at his feet he will see us.” He said, “What do you think, O Abu Bakr, of two people of whom Allah is the third?” (Narrated by al-Bukhari, 3380; Muslim, 4389)
This is a summary of the events of the hijrah. Whoever wants to know more may consult references such as al-Bidayah wa’l-Nihayah by Ibn Kathir, 4/168-205.
And Allah knows best.