Faith would be a believer of God. Although theres obvious evidence, there isnt a revealed truth. Yet.
Faithfulness is a loyal servant of God who has been in his presence before.
But if you arent faithful, you dont have faith.
If you have faith, you will be faithful.
It depends how you look at it.
Job had faith in God through his time of trouble.
God appeared to him and gave Job his posessions back. God even doubled them. Job is now faithful to his creator who was revealed.