Sin

[HebrewsTen24]

An associate of mine objects to the Catholic church because of various teachings. One being that sin is viewed as mortal and venial. Please share the background (history & Biblical support) of the distinction between sin-types and why all sin is not the same.

The questions I have been asked to respond to is:
If God is Holy and therefore will not allow allow sinful beings in his presence, why is not venial sin, just as bad as mortal?
Who made the distinction between types of sin?
Is it not just a “man-made” doctrine? Where is the Biblical support for this?

 

[Jim_Blackburn]

All sin is offensive to God but Scripture tells us that not all sin is mortal: “If any one sees his brother committing what is not a mortal sin, he will ask, and God will give him life for those whose sin is not mortal. There is sin which is mortal; I do not say that one is to pray for that. All wrongdoing is sin, but there is sin which is not mortal.” (1 Jn 5:16-17)

Mortal sin deprives the sinner of sanctifying grace, whereas venial sin does not. The Catechism of the Catholic Church explains that, for sin to be mortal, three conditions must be present: “Mortal sin is sin whose object is grave matter and which is also committed with full knowledge and deliberate consent.” (CCC 1857)