Have you read the second chapter of the Epistle of James? 

What good is it, my brothers and sisters, if you say you have faith but do not have works? Can faith save you? If a brother or sister is naked and lacks daily food, and one of you says to them, ‘Go in peace; keep warm and eat your fill’, and yet you do not supply their bodily needs, what is the good of that? So faith by itself, if it has no works, is dead. -- James 2:14-17

Catholics know that we are saved by faith -- we have read the Epistle to the Romans. We also know that if your faith does not change the way you act, then your faith is a sham.