Charles Ellicott Commentary James 2:20

"But wilt thou know, O vain man, that faith apart from works is barren?" — James 2:20 (ASV)

But wilt thou know, O vain man, that faith without works is dead?—“Vain,” that is, empty and useless. Some copies have a word which means idle, fruitless, workless, in place of that translated “dead”; but the sense is the same either way.

“If,” says Bishop Beveridge, “I see fruit growing on a tree, I know what tree it is on which such fruit grows. And so, if I saw how a man lives, I know how he believes. If his faith is good, his works must also be good; and if his works are bad, his faith must also be bad: for, wherever there is a justifying faith, there are also good works; and wherever there are no good works, there is no justifying faith.”

Works are the natural fruit of faith; and without them it is evident the tree is dead, perhaps at the very roots, ready to be cut down and cast into the fire.