The Messenger of Allah faced the relentless and untiring plot of the unbelievers without any weapons except the weapon of firm belief in Allah and in His promise and without any strength except strength of determination and willfulness.
At that time the Prophet could not defend the few believers who followed him from the torment mercilessly inflicted upon them by their own people. Especially since his followers, in addition to being few in number, were scattered between the various different tribes. They shared the difficulties of ostracism along with the Messenger of Allah and in most cases were unable to reveal their Islam or invite others to it. The believers were strangers in their own tribes and amongst their own people and their leader was the strangest one of all in his tribe and amongst his people.
That was because the believers had no homeland of their own and no tribespeople to defend them. Therefore whenever someone accepted Islam he had to stay with his own people especially if he lived outside of the city of Mecca. So they concealed their religion and waited for the command of the Prophet and his permission to emigrate.
The Messenger of Allah found himself compelled in the face of the harm inflicted by the unbelievers and their oppression of his followers - especially in the city of Mecca - to look for a timely solution that would protect the believers from the hardships and trials they were experiencing. Ethiopia at that time was a land that enjoyed a just ruler who did not allow oppression - his name was An-Najashi and it is from here that the story of the immigration of the believers to Ethiopia begins.
In an authentic hadith narrated upon the authority of 'Aisha who said: "I don't remember my parents believing in any religion other than the religion of Islam and (I don't remember) a day passing without our being visited by the Messenger of Allah at both ends of the day, once in the morning and once in the evening. When the Muslims were put to test (i.e. troubled by the pagans), Abu Bakr set out migrating to the land of Ethiopia. When he reached Bark Al-Gimad Ibn Ad-Daghina, the chief of the tribe of Al-Qaara, met him and said: 'Where are you going Abu Bakr?' Abu Bakr replied: 'My people have turned me out (of my country), so I want to wander the earth and worship my Lord!' Ibn Ad-Daghina said: 'O Abu Bakr! A man like you should not leave his homeland, nor should he be driven out because you help the poor, and you keep good relations with your kith and kin, you help the weak and poor, you entertain guests generously, and you help the calamity stricken persons. Therefore I am your protector. Go back and worship your Lord in your town.' So Abu Bakr returned and Ibn Ad-Daghina accompanied him. In the evening Ibn Ad-Daghina visited the nobles of the Quraish and said to them: 'A man like Abu Bakr should not leave his homeland, nor should he be driven out. Do you (Quraish) drive out a man who helps the poor, keeps good relations with his kith and kin, helps the weak and poor, entertains guests generously and helps the calamity stricken persons?' The Quraish could not refuse Ibn Ad-Daghina's protection and they said to Ibn Ad-Daghina: 'Let Abu Bakr worship his Lord in his house. He can pray and recite there whatever he likes, but he should not hurt us with it, nor should he do it publicly, because we are afraid that he may affect our women and children.' Ibn Ad-Daghina told Abu Bakr all of that?"
Abu Bakr was turned out of his homeland in spite of the fact that he was a good man, as is evidenced by Ibn Ad-Daghina's description of him to the Quraish and their response to it. Therefore Abu Bakr told Ibn Ad-Daghina that he wanted to wander the earth -without specifying his destination- so that he could worship his Lord.
Because of Abu Bakr's status amongst the people of the city of Mecca, the pagans singled him out for harm and punishment. There were a number of other emigrants with similar status who were also singled out for punishment such as Ja'far ibn Abee Taalib, 'Uthman ibn 'Affan, Abee Hudhaifa ibn 'Utba ibn Rabi'ah as well as others. However the majority of those who emigrated all experienced various types of punishments including beatings and torture and it was for this reason that the Messenger of Allah ordered them to migrate to Ethiopia.
In a hadith narrated upon the authority of Umm Salama who said: 'When (the oppression we were experiencing in) Mecca became very difficult for us, and the companions of the Messenger of Allah were being tortured and punished. And when they saw what was befalling them of tests and trials in their religion and that the Messenger of Allah was unable to defend them, and that he was protected by his uncle and his tribesmen (i.e. the sub-tribe of Bani Abd-Al-Muttalib) and therefore was not being tortured and punished the way his companions were. The Messenger of Allah said to them: 'Verily in the land of Ethiopia there is a king who does not oppress anyone so emigrate to his country until Allah makes a way for you.' So we departed for Ethiopia in small groups until we all gathered there and settled in a good land and with a good benefactor (i.e. An-Najashi) who left us to safely practice our religion and we never feared any oppression from him?"
No doubt the command to immigrate to Ethiopia relieved some of the difficulties faced by the companions of the Messenger of Allah. However the Prophet was compelled to suggest it because, as of yet, there was no homeland for Islam that the immigrants could seek refuge in. So the first immigrants really felt the separation from their native country even though they enjoyed the newfound religious freedom and safety from harm and oppression?it was the only suitable solution at that time until Allah strengthened Islam and gave it an established homeland.
For these reasons as well as others the Messenger of Allah and his companions faced ostracism and separation from their homeland during the rise of Islam. Various aspects of these hardships have been preserved in many authentic hadith.