Sahih Muslim Book 31, Hadith Number 5928.
Chapter : Merits of Sa’d b. Abi Waqqis (Allah be pleased with him).
‘Abdullah b. Shaddad reported that he heard saying: Allah’s Messenger (may peace be upon him) did not gather his parents except in case of Sa’d b. Malik that he said to him on the Day of Ubud: Shoot an arrow, may my father and mother be taken as ransom for you.