The Book Pertaining to the Merits of the Companions (Allah Be Pleased With Them) of the Holy Prophet (May Peace Be Upon Him) (Kitab Al-Fada'il Al-Sahabah)
Muslim :: Book 31 : Hadith 5934
This hadith has been transmitted on the authority of Simak and the hadith transmitted on the authority of Shu'ba (the words are): When they intended to feed her (Sa'd'. s mother), they opened her mouth with the help of a stick and then put the feed in her mouth, and in the same hadith the words are: He struck the nose of Sa'd and it was injured and Sa'd had (the mark) of wound on his nose.