al-israa' and al-mi`raj (the night journey and ascension) refer to the miraculous journey that prophet muhammad (peace and blessings be upon him) experienced. unlike what some people claim, that journey involved both the body and soul of the prophet. the main proof of the fact that the body of the prophet was involved in the journey is that almighty allah began the first verse of surat al-israa' by the word subhan, which means exalted and glorified. this word indicates that a miraculous event is about to be mentioned in the sequel.
this journey was a decisive stage of the prophet's call in makkah, because there were several cases of people embracing islam and others leaving it after this incident. abu bakr, the companion of the prophet, received his title as-siddiq (arabic for the very sincere) after this incident. he was the first to believe in the truthfulness of all events of this journey as narrated by the prophet.
on that night, jibreel came to the prophet and told him to circumambulate the ka`bah seven times. at the ka`bah, jibreel told him that he (prophet muhammad) was going to al-aqsa mosque, wherefrom they shall both ascend the seventh heaven to meet almighty allah.
in fact, you should prepare yourself for that day when you shall meet him. will you be happy on that day? or will you be ashamed of what you did during your life?
almighty allah says,
[glory be to him who took 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; surely, he, only he, is the hearer, the seer [of all things].]