At Golgotha, Jesus saves us from sin by becoming sin for us. Jesus takes all our messes, all our shame, all our guilt, all our fears and insecurities and He allows them to kill Him instead of us.
Jesus was praying a Psalm. Psalm 22 to be precise, and both the Gospels of Matthew and Mark relay the story to us of Jesus praying that Psalm on the cross at the hour of His death.
That man you see on the tree—he is the re-Genesis of the world. He has come to remake us alive and free and beautiful on the Friday of his crucifixion.