In Exodus 19:20 God came down on Mount Sinai and then in Exodus 31:18 He wrote the Law on two tablets of stone with his finger.
In John chapter 8 Jesus came into the temple and wrote on the stone floor with His finger. This is the passage where the Pharisees bring before Jesus a woman caught in adultery and test Him on His response to the clear instruction in the Law to stone her. Jesus replies with the now classic phrase “He who is without sin among you, let him be the first to throw a stone at her”.
My paraphrase of Exodus 31:18 – God stooped down and wrote on the stone with His finger
My paraphrase of John 8:6 – Jesus stooped down and wrote on the stone with His finger
I’ve heard the question asked about Jesus in John 8 “what was He writing?” Wrong question – the question is “why was He writing on the stone floor with His finger”. And the answer is – because He is the same God who did it with Moses so long ago.
The lesson that Jesus was giving was:“You want to use the law? I wrote that law! You’re just as guilty as she is and you’ve missed that it’s all about relationship with me.”
This is repeated in James 2:10-13 which basically says “you want to uphold the law? If you accuse someone of adultery and you commit murder you’re just as guilty. Mercy triumphs over judgement.”
The law was a fence to keep people on the path so they would find their way to God. All the Pharisees could see was the fence. Jesus turns up as the end of the pathway and the Pharisees are still studying the thickness of the wire and the gap in the mesh.