First Blood Drawn for Islam
In the early days of Islam when the Muslims would pray in secrecy, on one occasion Hazrat Sa‘d (ra) was offering prayers in one of the valleys around Mecca along with some other companions. The idolaters saw them and began making fun of the Muslims and criticising Islam, to the extent that it led to a quarrel. Hazrat Sa‘d (ra) hit one of the idolaters over the head with a bone of a camel, with such force that his head was cut open. Thus, this was the first blood that was drawn for Islam.
(Al-Isabah fi Tamyeez al-Sahabah, Vol. 2, p. 324, , Dar-ul-Fikr, Beirut, 2001)