In Christianity, all sin generates a need to confess and ask God's forgiveness. Not all sins, however, are equivalent in the eyes of God or society at large, according to Catholic Answers.
According to Christian tradition, the scriptures explicitly state that even a small, unprofessed or unforgiven sin is enough to warrant a sinner to be condemned to hell. Some sins, however, are so severe that they generate more severe judgment. The Catholic Church, in particular, separates sin into two categories: venial and mortal. Venial sins are smaller offenses. Mortal sins are those that are so severe that they alter the character of a person in such a way as to render his or her salvation in jeopardy.
Mortal sins are not reserved to acts themselves but the level to which an individual commits sin as well. In other words, if two people commit a sin, both are guilty in the eyes of God. However, if one of those two people commits the sin multiple times but the other only once, God judges the two accordingly. The severity of sins is also viewed similarly in the eyes of God. In other words, committing a sin, such as murder, is offensive to God. Committing that same sin in a particularly heinous manner is even more so.