What is the link between the law, sin?

What is the connection between the law and sin?
It’s in the Bible, I John 3:4, KJV. “Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law.”
So, umm … Is it necessary to keep all of God’s law? It’s in the Bible, James 2:10-11, NIV.
‘For whoever keeps the whole law and yet stumbles at just one point is guilty of breaking all of it. For He who said, ‘Do not commit adultery,’ also said, ‘Do not murder.’ If you do not commit adultery but do commit murder, you have become a lawbreaker.’
If we know Jesus, we will keep His commandments. It’s in the Bible, I John 2:4-6, NIV.
“The man who says, ‘I know Him,’ but does not do what He commands is a liar, and the truth is not in him.
But if anyone obeys His word, God’s love is truly made complete in him.
This is how we know we are in Him: Whoever claims to live in Him must walk as Jesus did.”
I am so glad I know Him and follow the footsteps of my Redeemer. I love Him for His unconditional love.

Michael
Port Moresby