The Messenger of Allah ﷺ stood up, i.e. on the day of Badr, and said: Uthman has gone off on the business of Allah and His Apostle, and I shall take the oath of allegiance on his behalf. The Messenger of Allah ﷺ then allotted him a share, but did not do so for anyone else who was absent.
إِنَّ رَسُولَ اللَّهِ ﷺ قَامَ يَعْنِي يَوْمَ بَدْرٍ فَقَالَ إِنَّ عُثْمَانَ انْطَلَقَ فِي حَاجَةِ اللَّهِ وَحَاجَةِ رَسُولِ اللَّهِ وَإِنِّي أُبَايِعُ لَهُ فَضَرَبَ لَهُ رَسُولُ اللَّهِ ﷺ بِسَهْمٍ وَلَمْ يَضْرِبْ لأَحَدٍ غَابَ غَيْرُهُ