The day of Mab’ath means the day when Prophet Mohammad (PBUH) was chosen as a prophet. He was the last prophet and no prophet has come after him. Mab’ath means the beginning of his mission: when the Prophet received the very first verses from his Lord; when he was meditating, and reflecting, and worshiping in Cave Hira in Mount Noor, just outside Mecca, on the suburbs of Mecca. For 10 years, the Prophet used to climb this mountain and stay in this cave.
Appointment of the prophet (Be’that) means being elected. The day of Mab’ath means the day when Prophet Mohammad (PBUH) was chosen as a prophet. He was the last prophet and no prophet has come after him.
