I think sin is sin – it’s all abhorrent to God. Why do Catholics distinguish between mortal and venial sins?
The distinction between mortal and venial sins is found in Scripture. St. John said the following: If anyone sees his brother sinning, if the sin is not deadly, he should pray to God and he will give him life. This is only for those whose sin is not deadly. There is such a thing as deadly sin, about which I do not say you should pray. All wrongdoing is sin, but there is sin that is not deadly (1 John 5:16-17). So, then, there is sin that is deadly (mortal), and sin that is not deadly (venial). Certainly it is all offensive to God, but it is not difficult to see that there is a difference between being unkind to a friend and taking someone’s life. Both are sins against love, but the second one is far more offensive than the first. It kills the life of grace — the share in God’s life — in us. Scripture provides various lists of sins that are considered particularly grave (Gal 5:19-21; Rom 1:28-32; Eph 5:3-5; Col 3:5-8). Committing a mortal sin involves meeting three conditions: the act i
