The Roman Catholic Church divides sin into two classes, making a distinction between “mortal” and “venial” sins. Mortal sin is described as a grave sin that must be confessed to a priest in order for the sinner to be reconciled to God and the Church. Venial sins, on the other hand, are small and pardonable offenses against God or our neighbor. Among priests there is no agreement as to which sins are mortal and which are venial. But the assumption among the Catholic clergy as well as among the laity is that such a distinction does exist. What is venial according to one may be mortal according to another.
One of the great purposes of the written Word of God is to show us that we are sinners. The Bible is a tutor that leads us to the perfect righteousness of Jesus Christ. Without the written record of God’s commandments we would be left to our own conscience and to the dictates of those in authority to define right and wrong. It is imperative that you understand what sin is and what is required of you. If you are being taught that there are varying degrees of sin and different means of removing the burden of that sin, you must be sure that the authority to which you are submitting is correct.
Whether or not some sins are greater than others, the most important issue before you is this: is there anything you can do about your sin?