Ali (AS)'s soul was the first to greet the Prophet (SAW)

He said: Abu Bakr Muhammad b. Umar al-Je'abi reported to me from Abu Abdillah Muhammad b. al-Qasim al-Muharibi, who reports from Ismail b. Ishaq al-Rashidi, who reported from Muhammad b. al-Harith, who reported from Ibrahim b. Muhammad, from Muslim al-A'awar, from Habbah al-Arni, from Abu al-Haytham b. al- Teehan al-Ansari, who reported that:

The Prophet, peace be upon him and his progeny, said: "Allah, Most High, created the souls two thousand years earlier then the bodies, attached it to the Throne and ordered them to greet me and obey me. So the first one among men who greeted me and expressed his obedience to me was the soul of Ali b. Abi Talib, peace be upon

him."

(Ref: Amali Shaikh Mufeed : The Thirteenth Assembly: Hadees No. : 6)