The seven mortal sins, traditionally known as the Seven Deadly Sins, are grave offenses in Christian moral teaching that can lead a soul away from God's grace if committed knowingly and willingly. While they're not listed as such in the Bible, they were formalized by early Church thinkers like St. Gregory the Great and later expanded by St. Thomas Aquinas. Here are the Seven Deadly (Mortal) Sins: 1. Pride – Excessive belief in one's own abilities or importance, often putting oneself above God. 2