What is the meaning of the "woman taken in adultery" story in John Chapter 8?

In my mini-'book' on the Fourth Gospel; I describe my assumptions in reading the Bible; which lead to me to the Fourth Gospel ("John") as the most authoritative Book; and which govern my interpretation of that Gospel. 

Much of this has to do with the unit of meaning that I focus upon - which is neither the Bible as a whole, nor a verse by verse (nor word by word) meaning; but more like a focus on the Book and the narrative-units within it. 

In particular, I pay attention to that which is repeated and re-explained - which I regard as less subject to later error, interpolations, and excisions.

To take a particular example: how do I look-at the episode from the IV Gospel often called "the woman taken in adultery" [see below for text]: What does this episode mean, how do I understand it?

For a start; I am aware of the overall and two-fold message of the IV Gospel; which is (approximately) that we each may have 'salvation' (i.e. eternal resurrected life) by 'following' Jesus. 

This overall message is stated several times, in different ways, throughout the Gospel from its beginning to its end (i.e. the verses at the end of Chapter 20 - Chapter 21 being, I believe, a later addition by another hand). 

In this episode the two-fold message is re-stated, using the frequent 'poetic-metaphor' of light;  in verse 12: Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life. 

This core 'Christian' message required, at the time, refuting a different and prevalent idea; which was that salvation was a matter of avoiding sin, and avoiding sin was a matter of following The Law. 

This is what I think this adultery episode is about. Jesus is confronted by a woman who has sinned, who has broken the law; and, by the old rule, was therefore legitimately 'condemned' to death - and thereby (by the then understanding of 'death') 'damned' to dwell as a depersonalized, demented ghost in Sheol. 

Jesus desires to replace this scheme with one in which death is not damnation; but instead resurrection to a higher, better, fully-loving eternal life in Heaven. 

And this Life Everlasting is to be attained Not by avoiding proscribed sins, but by following Jesus. 

On the one hand; Jesus asserts that it is futile to suppose that we can avoid sin. This story demonstrates that we are all sinners, and therefore there is 'nothing special' about the woman taken in adultery. By the old religion we are all in the same boat as her; all 'deserving' of death for transgressing one or more of The Laws, therefore all destined for damnation (later, if not sooner)...

(In this regard; it needs to be remembered that in the IV Gospel, 'sin' and 'death' are almost synonymous. This is a key that unlocks many otherwise rather obscure passages.)

But the 'good news' Jesus brings and makes possible; is that none of this endemic and universal sinning ultimately matters if we choose follow Jesus; where 'following' means (almost literally) recapitulating his path from this mortal life, through death, and to resurrection in Heaven.

(We are made able to follow Jesus by loving him; which partly means wanting and affirming and committing-to God and divine creation; and this includes rejecting sin/ death. Sin is whatever conflicts with love; and therefore must be repudiated to dwell in Heaven. This is what we term repentance.)

That is what I understand this story to mean, and which fits with the reality and essential nature of Jesus, and with the Gospel as a whole and its repetitions - and therefore I pretty much ignore those specific verses that clash or contradict. 

For example when Jesus is quoted as saying to the woman 'sin no more'; then I note that this is literally false; because it is impossible Not to sin, as Jesus has just demonstrated; therefore this phrase is either a later and mistaken interpolation (which is what I assume), or else must be interpreted in a very contextualized meaning (if you can be bothered!).

Or, what about the business of Jesus writing on the ground? That is obscure, and might be incomplete (due to some later loss or deletion), interpolated; or else the act had some then-understandable 'metaphorical/ poetic' meaning, that has since been lost. 

But it does not really matter - and we need not get hung-up on it; once we understand the necessary and core meaning of the episode as a whole.

So, this is a specific example of how I read the IV Gospel, how I go-about discerning truth from error.

If there are other bits of the IV Gospel that you are seriously confused or 'hung-up' on; you might mention them in the Comments; and I may try to demonstrate how I have understood them - according to this scheme. 

   

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John.8 [1] Jesus went unto the mount of Olives. [2] And early in the morning he came again into the temple, and all the people came unto him; and he sat down, and taught them. [3] And the scribes and Pharisees brought unto him a woman taken in adultery; and when they had set her in the midst, [4] They say unto him, Master, this woman was taken in adultery, in the very act. [5] Now Moses in the law commanded us, that such should be stoned: but what sayest thou? [6] This they said, tempting him, that they might have to accuse him. But Jesus stooped down, and with his finger wrote on the ground, as though he heard them not. [7] So when they continued asking him, he lifted up himself, and said unto them, He that is without sin among you, let him first cast a stone at her. [8] And again he stooped down, and wrote on the ground. [9] And they which heard it, being convicted by their own conscience, went out one by one, beginning at the eldest, even unto the last: and Jesus was left alone, and the woman standing in the midst. [10] When Jesus had lifted up himself, and saw none but the woman, he said unto her, Woman, where are those thine accusers? hath no man condemned thee? [11] She said, No man, Lord. And Jesus said unto her, Neither do I condemn thee: go, and sin no more. [12] Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life.