Your Bible doesn't have the 10 Commandments!!??
He forgets the passage in 1 John 5:16,17
16: 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.
17: All wrongdoing is sin, but there is sin which is not mortal.
Right there are the two classes of sin. Mortal, and those that are less than mortal, which we call venial.
Are you committing a mortal or venial sin if you break one of the Commandments? Let me know if you also keep all of the Mosaic Laws listed in Leviticus. You do keep all of them, don't you? You are still under the yoke of the law, aren't you?