Without faith we can do no good for nothing in man is harmless...

Therefore, it is easy to see that this doctrine is not to be accused of banning good works.  Instead, it is to be commended all the more because it shows how we are enabled to do good works.  For without faith, human nature cannot, in any way, do the works of the First or Second Commandment.  Without faith, human nature cannot call upon God, nor expect anything from Him, nor bear the cross.  Instead human nature seeks and trusts in human help.  So when there is no faith and trust in God, all kinds of lusts and human intentions rule in the heart.  This is why Christ says, "Apart from me you can do nothing" (John 15:5). That is why the Church sings: "Lacking Your divine favor, there is nothing in man.  Nothing in him is harmless."
~BOC, AC, XX, 35-40