Confrontation with his Father at the battle of Badr
Hazrat Abu Ubaidah bin Jarrah (ra) took part in all the battles alongside the Holy Prophet (sa), including the Battle of Badr and Uhud.
(Ibn Sa‘d, al-Tabaqat al-Kubra, Vol. 3 [Beirut, Lebanon: Dar al-Kutub al-‘Ilmiyyah, 1990] 313.)
Hazrat Abu Ubaidah bin Jarrah was 41 years old at the time of the Battle of Badr.
(Ibn Sa‘d, al-Tabaqat al-Kubra, Vol. 3 [Beirut, Lebanon: Dar al-Kutub al-Ilmiyyah, 2012] 316.)
On the day of the Battle of Badr, Hazrat Abu Ubaidah bin Jarrah (ra) entered the battlefield on the side of the Muslims and his father, Abdullah fought on the side of the disbelievers and both father and son encountered one another. His father made him the target during the battle; however, Hazrat Ubaidah (ra) would outmanoeuvre him. That is, he would escape to one side whilst protecting himself.
Nevertheless, his father continued to pursue after him and was intent on killing him one way or another. Hazrat Abu Ubaidah (ra) also had the chance to kill his father, but he avoided him so that he would not have to kill him and at the same time continued to evade him.
When Hazrat Ubaidah (ra) saw that his father was not leaving him alone, his passion and honour for the unity of God transcended beyond that for his family ties. Upon seeing that his father was intent on killing him, simply because he had believed in the unity of God, his family relations were reduced to nothing.
Furthermore, it is written in narrations that when Hazrat Abu Ubaidah (ra) saw that his father was not stopping in his pursuit to kill him, his passion and honour for the unity of God transcended all family ties and Abdullah, the father of Hazrat Ubaidah bin Jarrah (ra) was killed at the hands of his own son. Ultimately, Hazrat Abu Ubaidah (ra) was left with no choice but to kill his father.
(Sheikh Shah Moinuddin Ahmad Nadvi, Siyar al-Sahabah, Vol. 2 [Karachi, Pakistan: Dar al-Isha’ah, 2004] 124.)