There were two main Hijra:-
1) Hijrah to Abyssinia (Ethiopia).
2) Hijrah to Madinah.
The Hijrah to Abyssinia.The unbelievers of Makkah had made life very difficult for the Muslims. The Prophet (S) told some Muslims to migrate to Abyssinia (Ethiopia), which was ruled by a kind Christian king whose name was Negus.
This was the first Hijrah in Islam. It happened 5 years after the Prophet (S) started his mission. First ten people went, then forty followed. The Muslims were shown much kindness in Abyssinia and found the life there very pleasant and comfortable.
When the chiefs of Makkah found out that the Muslims had migrated and were living peacefully in Abyssinia, they sent two men to the king of Abyssinia, to try to convince him to send the Muslims back to Makkah.
The king asked if the Muslims had committed any crimes in Makkah. When he was told that their only crime was inventing a new religion, the King asked to speak to the leader of the Muslims, who was Imam Ali's (A) brother, Ja'far.
The king turned to Ja'far and asked, "Why have you given up the beliefs of your forefathers and started a new religion?"
Ja'far replied, "We used to be ignorant people who worshipped idols. We committed bad deeds. We had no respect for our neighbours and fought amongst ourselves. The weak were bullied by the strong. We spent a long time in this manner, until the Prophet (S), invited us to worship One God.
The king asked Ja'far, to recite something from the Book of the Muslims. Ja'far recited and explained some verses from Surah Maryam of the Holy Qur'an.
When the king and bishops heard the words of Allah about the Bibi Maryam (A) and Prophet Isa (A), tears came to their eyes as they recognised the truth. King Negus declared that he would never surrender the Muslims to the Quraysh and asked them to leave his court.
The Hijrah to Madinah.When the Quraysh realised that the Muslims now had the support of the people of Madinah, they were very angry. They increased their efforts at bullying and harassing the Muslims.
The Prophet (S) advised all the Muslims to migrate to Madinah secretly, and await his arrival there.
The Quraysh realised that the Muslims were all leaving Makkah. They managed to stop a few, but by that time the majority had already escaped and were on their way to Madinah.
In Makkah there only remained the Prophet (S) and his family, Imam Ali (A) and a few old and ill Muslims. These last few Muslims were also about to leave.
The Quraysh were very angry at this mass escape. They knew that the Muslims would now become a danger to them. They decided that the only action that would stop the spread of Islam would be to kill the Prophet (S).
The only problem was the revenge that the Bani Hashim, the family of the Prophet (S), would take on the killer. Finally, they decided that instead of sending one man to kill the Prophet (S), they would send one young man from each tribe. That way, it would be impossible to lay the blame on any one person. This plan was approved and 40 young men were selected to carry out the cowardly deed.
On the same night that the Quraysh planned to kill the Prophet (S), he was commanded by Allah to leave Makkah for Madinah. Angel Jibraeel (A) informed the Prophet (S) of the wicked intentions of the Quraysh.
The Prophet (S) turned to Imam Ali (A) and said, "Sleep in my bed tonight and cover yourself with the green sheet that I use when I sleep."
He then told Imam Ali (A) to follow him to Madinah after he had returned the property that certain people of Makkah had left with the Prophet (S).
Imam Ali (A) was quite content to obey the orders he had been given because he knew that his actions would mean the safety of the Prophet (S). He used to say in later years that in spite of the deadly danger, he slept peacefully the whole night.
As night approached, the house of the Prophet (S) was surrounded by the 40 men of Quraysh. They decided to wait till the morning before carrying out their assignment.
When half the night was over, the Prophet (S) left his house to begin his journey. As he came out of the house he threw some sand towards the men who were waiting to kill him and recited the following verse:
And We have set before them a barrier and behind them a barrier and We covered them over so that they do not see. (Surah Ya Sin, 36:9)In the morning the men burst into his house and rushed to the bed making a great noise as each tried to be first to strike a blow. On hearing the commotion, Imam Ali (A) calmly raised his head from the pillow and threw the green sheet aside.
The sight of Imam Ali (A) stopped the would-be killers in their tracks. "Where is Muhammad?", they demanded. Imam Ali (A) replied, "Did you hand him to me, so that I may deliver him back to you? Anyway, he is not in the house at present."
The Quraysh were angry at their failure but they left Imam Ali (A) unharmed because they had no quarrel with him. They left the house, regretting their decision to wait till the morning.
It is from this year that Muslims mark the beginning of the Islamic Calendar.
(Courtesy of:- Shia Ithna asheri Madressa)