Which Sahaba killed his father?

Answer:

In the year 624, Abu Ubayda took part in the pivotal clash between the Muslims and the Quraysh of Mecca known as the Battle of Badr. During this confrontation, he encountered his father, Abdullah ibn al-Jarrah, who was aligned with the Quraysh forces. As Abdullah ibn al-Jarrah launched an attack on his son with his sword, Ubaydah ultimately fatally struck him down.