Answer :
He left because there was a plot to assassinate him, then encouraged other Muslims to leave and I'll go to Madina.
For the next two years, groups of people from Medina came to Mecca and converted to Islam. This inspired Muhammad, who instructed all Muslims to settle in Medina. In 622, Muhammad fled Mecca after hearing of a plot to assassinate him. ... This journey is known as the Hijrah, and it holds special significance to Muslims.