Q: What's the difference between a Nabi and a Rasool?
A: Imam Fakhruddeen Raazi has explained the differences between a Rasool (prophet) and a Nabi (messenger). A Rasool is one who has performed miracles and has received a new Divine book. He establishes a new code of law (Shar'iah) and abrogates the previous code of law and book. He has also visibly seen the angel that comes with the Divine message, and the Rasool is commanded to invite the people towards the Deen.
A Nabi is one who is not given a new book, but rather establishes the book which was revealed to the Rasool before him. He does not abrogate the book and the code of law which was in vogue before him. He sees the angel in a dream or the Rasool of the time informs him that he has been chosen as a Nabi. (Tafseer Raazi V1 p3212, Mafaateehul Ghayb V23 p43)
Moulana Yusuf Laher
Checked and approved by: Mufti Siraj Desai