[Machine] Abu Ubaydah was appointed by his father to confront Abu Ubaydah on the day of Badr. Abu Ubaydah avoided him, but when his intention became clear, Abu Ubaydah killed him. Allah then revealed this verse when he killed his father: "You will not find a people who believe in Allah and the Last Day [making friends] with those who oppose Allah and His Messenger" until the end of the verse.
جَعَلَ أَبُو أَبِي عُبَيْدَةَ يَتَصَدَّى لِأَبِي عُبَيْدَةَ يَوْمَ بَدْرٍ فَجَعَلَ أَبُو عُبَيْدَةَ يَحِيدُ عَنْهُ فَلَمَّا أَكْثَرَ قَصَدَهُ أَبُو عُبَيْدَةَ فَقَتَلَهُ فَأَنْزَلَ اللهُ ﷻ فِيهِ هَذِهِ الْآيَةَ حِينَ قَتَلَ أَبَاهُ {لَا تَجِدُ قَوْمًا يُؤْمِنُونَ بِاللهِ وَالْيَوْمِ الْآخِرِ} إِلَى آخِرِ الْآيَةِ