Abu Sa’eed al-Khurdi or al-Khidri is considered as one of the pious companions of the Prophet (Peace be Upon Him and His Holy Progeny). He was with the army of Ameerul Momeneen Ali (A.S.) fighting against his enemies. Ameerul Momeneen asked the companions who from you witnessed the incident of Ghadeer Khum. Only 17 man stood up and gave witness among them was Abu Sa’eed al-Khudri. He lived long as he was born 10 years before Hijra and he passed away in year 73 after Hijra, so his age was 83 years. From Imam Jafar as-Sadiq (A.S.) about him that he was a straight forward person. Al-Khishyee mentioned in the life of ibne Masa’ood and Huzaifa the names of the companions who referred to Ameerul Momeneen the name of Abu Sa’eed al-Khudri was with them. Al-Allama in his book Al-Khulaasa narrated from Al-Burqi that Abu Sa’eed al-Khudri was from the companions of Ameerul Momeneen Ali (A.S.). Abu Sa’eed al-Khidri is buried in Al-Baqiyah. His Name was Sa’aad Bin Malik Bin Sinaan and his Kunniyah was Abu Sa’eed. He was from the Al-Ansaar from Bani Khidra or Khurda.
In the reply which Imam Ali Ibne Moosa Ar-Reza (A.S.) has written to Al-Ma’moon about those companions who were following Ameerul Momeneen (A.S.) after the Prophet and did not change, he mentioned the name of Abu Sa’eed al-Khudri. Imam Hussain (A.S.) in Karbala in his speech told the army of Yazeed that you can ask Abu Sa’eed al-Khudri. The first battle in which Abu Sa’eed al-Khudri participated was Al-Khandaq than he took part in 12 other battles with Prophet (S.A.W.A.)
May Allah (SWT) bless his soul.