This question arose when I spoke with some Roman Catholic people. I mentioned that all of our sins were forgiven at the time when Jesus shed the blood and died at the Cross. RC mention about the Prayer taught by Lord (Mt 6) teaches us to ask for the forgiveness of our sins. This is why RC conduct the Mass every week where Catholic priests ask God for the forgiveness of the sins confessed by the people during the week. How is your belief? Were our future sins forgiven already? or do we have to ask for the forgiveness for the future sins each time when we discover the sins committed by us?