"Glory to ((Allah)) Who did take His servant for a Journey by night from the Sacred Mosque to the farthest Mosque, whose precincts We did bless,- in order that We might show him some of Our Signs: for He is the One Who heareth and seeth (all things)." [Al-Quran ~ Al-Isra'(17):1]
Israa': Was the prophet's trip from Makkah to Masjid al-Aqsa in Jerusalem
Mi'raj: Was the Prophet's journey to Heaven.
It is one of the miraculous experiences that Allah has blessed and honored prophet Muhammad (peace be upon him) with.
The Prophet (pbuh) and the small group of early Muslims in Makkah had been suffering extensively from the Arab pagans of the Quraish tribe. The distress further increased when the Prophet went to the city of Taif where he was humiliated by the people of Taif who pelted him with stones. In this state of anguish, and a feeling of helplessness in front of his enemies he turned to Allah and made a fervent supplication. He ended the supplication by saying that as long as Allah is not displeased with him, then he will always be satisfied. Right after this event, the Israa and Miraj took place to honor him and to renew his courage and strive to serve Allah.
The experience was also a sign that all prophets go through hardship and that Allah was not displeased with him. There are many lessons we can also learn from the experience such as the truth of Islam, the full confidence of Abu Bakr in the prophet's trustworthiness, the establishment of the prayers, the importance of Jerusalem and its holy sites, etc.
Narrated Abu Huraira
On the night Allah's Apostle was taken on a night journey (Miraj) two cups, one containing wine and the other milk, were presented to him at Jerusalem. He looked at it and took the cup of milk. Gabriel said, "Praise be to Allah Who guided you to Al-Fitra (the right path); if you had taken (the cup of) wine, your nation would have gone astray."
(Note : 27th Rajab 1430 this year falls on 20th July 2009)