Ubaidullah bin Musa bin Abi al-Mukhtar عبيد الله بن موسى بن أبي المختار باذام · The Chapters on Jihad

“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.”