27 Rajab Amaal
The Day of Mab’ath, celebrated on the Rajab 27, is indeed the formal appointment as the Last and Greatest Divine Messenger of the person whose light God had created as the first ever creation eons ago when nothing had yet come into existence.
This is an occasion which stands for the beginning of the Holy Prophet’s Mission of promulgating the true religion of Almighty Allah (swt).
On this day, the Holy Prophet (peace be upon him and his household) was appointed for conveying the Divine Mission of Almighty Allah when Archangel Gabriel first came to him with the Divine Revelation.
It is recommended to have Ghusl (bath) on this day & observe Fasting. This day is one of the four days that are specified for highly recommended fasting during the whole year. The reward of observing fasting on this day is mentioned to be equal to seventy years fasting.
It is recommended to repeat very frequently the salwat ie sending blessings upon Prophet Muhammad and his Household.:-
O Allah, (please) bless Muhammad and the Household of Muhammad.
اللَّهُمَّ صَلِّ عَلَىٰ مُحَمَّدٍ وَآلِ مُحَمَّدٍ