It was narrated that Bara’ bin ‘Azib said:
“We were talking about how, on the Day of Badr, the Companions of the Messenger of Allah ﷺ numbered three hundred ten and something, the same number as the Companions of (Talut) who crossed the river with him, and no one crossed the river with him but a believer.”

حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا أَبُو عَامِرٍ، حَدَّثَنَا سُفْيَانُ، عَنْ أَبِي إِسْحَاقَ، عَنِ الْبَرَاءِ بْنِ عَازِبٍ، قَالَ كُنَّا نَتَحَدَّثُ أَنَّ أَصْحَابَ، رَسُولِ اللَّهِ ﷺ كَانُوا يَوْمَ بَدْرٍ ثَلاَثَمِائَةٍ وَبِضْعَةَ عَشَرَ عَلَى عِدَّةِ أَصْحَابِ طَالُوتَ مَنْ جَازَ مَعَهُ النَّهَرَ وَمَا جَازَ مَعَهُ إِلاَّ مُؤْمِنٌ .