works
Compare (James 2:24).
These are two aspects of one truth. Paul speaks of that which justifies man before God, namely: faith alone, wholly apart from works; James of the proof before men, that he who professes to have justifying faith really has it. Paul speaks of what God sees -- faith; James of what men see -- works, as the visible evidence of faith. Paul draws his illustration from (Genesis 15:6) James from (Genesis 22:1-19). James' key phrase is "ye see" (James 2:24) for men cannot see faith except as manifested through works.