Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)

Bukhari :: Book 5 :: Volume 59 :: Hadith 294

Narrated Al-Bara:

We, the Companions of Muhammad used to say that the number of the warriors of Badr was the same as the number of Saul's companions who crossed the river (of Jordan) with him, and none crossed the river with him but a believer, and the were over three-hundred-and-ten men.