Al Qur’an, Sura 17 (Al-Isra) Ayah 1:
Exalted is He who took His Servant by night
from al-Masjid al-Haram to al-Masjid al- Aqsa*,
whose surroundings We have blessed,
to show him of Our signs.
Indeed, He is the Hearing, the Seeing.
- – this has also been translated as ‘the Farthest Mosque’ and an interpretation is that it does not refer to the Al Aqsa Mosque in Jerusalem.
In Trinidad, miraj-un-Nabi is observed/commemorated, most usually, by lectures. In Barbados, I find it noted almost in silence.
The miraj is the Ascent of Rasool saws to the Heavens referred to in the above-quoted ayah, and debates abound as to whether it was a physical or only spiritual ascent. Many details of the Ascent are given in hadiths, and span the carrying of Rasool saws astride the winged steed Buraq from the Holy Kaaba to Masjid al-Aqsa in Jerusalem, his prayers with other Prophets a.s. to his ascent to the Heavens, his meeting with several Prophets a.s., his meeting with Allah swt, the gift of obligatory salaah, and his return to Mecca via Jerusalem.
Allah swt says in Al Qur’an Sura 17 Ayah 44:
The seven heavens and the earth and whatever is in them exalt Him. And there is not a thing except that it exalts [ Allah ] by His praise, but you do not understand their [way of] exalting. Indeed, He is ever Forbearing and Forgiving.