The Book of Oaths
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، وَعَمْرٌو النَّاقِدُ، وَزُهَيْرُ بْنُ حَرْبٍ، قَالُوا حَدَّثَنَا سُفْيَانُ، بْنُ عُيَيْنَةَ عَنِ الزُّهْرِيِّ، عَنْ سَالِمٍ، عَنْ أَبِيهِ، قَالَ سَمِعَ النَّبِيُّ صلى الله عليه وسلم عُمَرَ وَهُوَ يَحْلِفُ بِأَبِيهِ . بِمِثْلِ رِوَايَةِ يُونُسَ وَمَعْمَرٍ .Salim reported on the authority of his father that Allah's Apostle (ﷺ) heard 'Umar while he was taking oath by his father. The rest of the hadith is the same
From Sahih Muslim, whose reports the scholars accept as authentic.