Jesus said, "Let him that is without sin throw the first stone." Well, seeing that He is the only one without sin, was Jesus essentially saying, 'leave all judgment to Me"? And when He said to the woman, "...neither do I condemn thee," was He suggesting His judgment the only one that counts as valid? When He asks, 'where are your accusers, does anyone condemn you?' speaking exclusively of accusers and she answered, 'no one' and His reply, "neither do I..." suggests His exclusion from "anyone," considering He is not just "anyone."...
So, essentially this is a lesson in leaving God's judgment to Him alone, we are not sufficiently skilled nor even capable of picking up that sword, let alone wielding it.