The primary difference between the Shia and Sunni is what happened after the Prophet died. The Shia believe that the Prophet had announced Ali as his heir at least two months before his impending death. Many Sunni books record the incident in which the Prophet publicly announced Ali to be his heir, returning back from the last pilgrimage or Hajj at a place called Ghadir-e-Khum, in front of ten thousand people.
Ali was personally raised by the Prophet since Ali was ten years old (The Prophet was thirty years older than Ali), and Ali, used to