Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) says: On the day of Badr, Sayyiduna Sa'd (may Allah be pleased with him) fought alongside the Prophet (peace and blessings be upon him) both as a horseman and as a foot soldier (that is, in both capacities).
Al-Bazzar recorded it with two chains, one of which is muttasil (connected) and the other mursal, and the narrators of both are thiqat (trustworthy).