1 John 3:4 observations

This morning a brother and I continued our study of 1 John. We go very slowly hoping to glean as much as possible. The NKJV of 1 John 3:4 reads "Whoever commits sin also commits lawlessness, and sin is lawlessness. The brother asked what law that the Bible is discussing in verse 4. The word "law" is used in several different ways in the Bible. Predominantly it is used of the law of Moses, the 613 old covenant commands including the 10 commandments. In rare instances it could refer to Roman or other secular law, and in the new covenant it can refer to the law of Christ. Other expressions for the law of Christ are the royal law or the law of liberty. So what is happening here. We went to Hebrews 8 and looked at verses 6,10, 11 and 12. Verse six indicates the change of covenants inaugurated by Jesus. Verse ten speaks of the new laws being written on the hearts of God's people. One way to understand this is a contrast between external law and internal law. Moses was instructed to write down the laws that God gave the people. In Hebrews 8:10 God says He will write the law in minds and hearts. Let's use a modern day example. Suppose I go into a convenience store. I go to pay for my purchase and discover that the cashier has accidentally left the cash drawer open and gone away to take care of some emergency. There is $1,000 in the drawer. The state law says that if I steal I could be arrested, tried, convicted and sent to jail. This is an external law. Perhaps i can get away with the theft and no one knows who did it. The internal law is something that God has done where even if there is $10,000 in the drawer I won't take it because i believe that this would displease Him rather than show my love for Him. ( The greatest commandment) Stealing would also violate the second most important commandment of loving my neighbor as myself. Would i want my neighbor to steal my money? If not then i should not steal his money. In effect then whenever i sin I am turning a blind eye towards the law of God written on my heart, taking an eraser and wiping it away. This is lawlessness.