You have to love the poetry of the King James Version:
Seest thou how faith wrought with his works, and by works was faith made perfect?
Or the more expounding Amplified Version:
You see that [his] faith was working together with his works, and as a result of the works, his faith was completed [reaching its maturity when he expressed his faith through obedience].
In any version the message is the same, true faith in God always results in works that prove our obedience to God.