The pericope adulterae (John 7:53-8:11) as a later interpolation

And every man went unto his own house. Jesus went unto the mount of Olives. 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. And the scribes and Pharisees brought unto him a woman taken in adultery; and when they had set her in the midst, they say unto him, Master, this woman was taken in adultery, in the very act. Now Moses in the law commanded us, that such should be stoned: but what sayest thou? This they said, tempting him, that they might have to accuse hi. But Jesus stooped down, and with his finger wrote on the ground, as though he heard them not. 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. Ad again he stopped down, and wrote on the ground. And they which heard it, being convicted by their own conscience, went out one by one, beginning at the least, even unto the last: and Jesus was left alone, and the woman standing in the midst. When Jesus had lifted up himself, and saw none but the woman, he said unto hr, Woman, where are those thine accusers? hath no man condemned thee? She said, No man, Lord. And Jesus said unto her, Neither do I condemn thee: go and sin no more. (John 7:53-8:11)

John 7:53-8:11 is a favourite among many readers of the Bible, as it contains the story of the woman taken in adultery. However, it is universally accepted, due to the overwhelming textual-critical evidence, that this pericope is a later interpolation into the biblical texts, and it not one to be used in preaching/in the formulation of doctrine (personally, I never use it, and if I have to discuss it, I use it as an opportunity to discuss New Testament textual criticism). For a full discussion of this pericope, see Philip W. Comfort, New Testament Text and Translation Commentary (Carol Stream, Illin.: Tyndale House Publishers, 2008), 285-88 (an excellent resource I highly recommend to serious students of the NT). The note accompanying John 7:53 does a good job at summarising the evidence of this pericope being an interpolation:

This entire section, Joh 7:53-8:11, traditionally known as the pericope adulterae, is not contained in the earliest and best MSS and was almost certainly not an original part of the Gospel of John. Among modern commentators and textual critics, it is a foregone conclusion that the section is not original but represents a later addition to the text of the Gospel. B. M. Metzger summarizes: "the evidence for the non-Johannine origin of the pericope of the adulteress is overwhelming" (TCGNT 187). External evidence is as follows. For the omission of Joh 7:53-8:11: î^{66, 75} ‌א‎‏‎ B L N T W Δ Θ Ψ 0141 0211 33 565 1241 1424* 2768 al. In addition codices A and C are defective in this part of John, but it appears that neither contained the pericope because careful measurement shows that there would not have been enough space on the missing pages to include the pericope Joh 7:53-8:11 along with the rest of the text. Among the MSS that include Joh 7:53-8:11 are D Û lat. In addition E S Λ 1424^mg al include part or all of the passage with asterisks or obeli, 225 places the pericope after Joh 7:36, ƒ¹ places it after Joh 21:25, 115 after Joh 8:12, ƒ¹³ after Luk 21:38, and the corrector of 1333 includes it after Luk 24:53. (For a more complete discussion of the locations where this "floating" text has ended up, as well as a minority opinion on the authenticity of the passage, see M. A. Robinson, "Preliminary Observations regarding the Pericope Adulterae Based upon Fresh Collations of nearly All Continuous-Text Manuscripts and All Lectionary Manuscripts containing the Passage," Filologia Neotestamentaria 13 [2000]: 35-59, especially 41–42.) In evaluating this ms evidence, it should be remembered that in the Gospels A is considered to be of Byzantine texttype (unlike in the epistles and Revelation, where it is Alexandrian), as are E F G (MSS with the same designation are of Western texttype in the epistles). This leaves D as the only major Western uncial witness in the Gospels for the inclusion. Therefore the evidence could be summarized by saying that almost all early MSS of the Alexandrian texttype omit the pericope, while most MSS of the Western and Byzantine texttype include it. But it must be remembered that "Western MSS" here refers only to D, a single witness (as far as Greek MSS are concerned). Thus it can be seen that practically all of the earliest and best MSS extant omit the pericope; it is found only in MSS of secondary importance. But before one can conclude that the passage was not originally part of the Gospel of John, internal evidence needs to be considered as well. Internal evidence in favor of the inclusion of Joh 8:1-11 (Joh 7:53-8:11): (1) Joh 7:53 fits in the context. If the "last great day of the feast" (Joh 7:37) refers to the conclusion of the Feast of Tabernacles, then the statement refers to the pilgrims and worshipers going home after living in "booths" for the week while visiting Jerusalem. (2) There may be an allusion to Isa 9:1-2 behind this text: Joh 8:12 is the point when Jesus describes himself as the Light of the world. But the section in question mentions that Jesus returned to the temple at "early dawn" (῎Ορθρου, Orthrou, in Joh 8:2). This is the "dawning" of the Light of the world (Joh 8:12) mentioned by Isa 9:2. (3) Furthermore, note the relationship to what follows: Just prior to presenting Jesus' statement that he is the Light of the world, John presents the reader with an example that shows Jesus as the light. Here the woman "came to the light" while her accusers shrank away into the shadows, because their deeds were evil (cf. Joh 3:19-21). Internal evidence against the inclusion of Joh 8:1-11 (Joh 7:53-8:11): (1) In reply to the claim that the introduction to the pericope, Joh 7:53, fits the context, it should also be noted that the narrative reads well without the pericope, so that Jesus' reply in Joh 8:12 is directed against the charge of the Pharisees in Joh 7:52 that no prophet comes from Galilee. (2) The assumption that the author "must" somehow work Isa 9:1-2 into the narrative is simply that - an assumption. The statement by the Pharisees in Joh 7:52 about Jesus' Galilean origins is allowed to stand without correction by the author, although one might have expected him to mention that Jesus was really born in Bethlehem. And Joh 8:12 does directly mention Jesus' claim to be the Light of the world. The author may well have presumed familiarity with Isa 9:1-2 on the part of his readers because of its widespread association with Jesus among early Christians. (3) The fact that the pericope deals with the light/darkness motif does not inherently strengthen its claim to authenticity, because the motif is so prominent in the Fourth Gospel that it may well have been the reason why someone felt that the pericope, circulating as an independent tradition, fit so well here. (4) In general the style of the pericope is not Johannine either in vocabulary or grammar (see D. B. Wallace, "Reconsidering 'The Story of the Woman Taken in Adultery Reconsidered'," NTS 39 [1993]: 290-96). According to R. E. Brown it is closer stylistically to Lukan material (John [AB], 1:336). Interestingly one important family of MSS (ƒ¹³) places the pericope after Luk 21:38. Conclusion: In the final analysis, the weight of evidence in this case must go with the external evidence. The earliest and best MSS do not contain the pericope. It is true with regard to internal evidence that an attractive case can be made for inclusion, but this is by nature subjective (as evidenced by the fact that strong arguments can be given against such as well). In terms of internal factors like vocabulary and style, the pericope does not stand up very well. The question may be asked whether this incident, although not an original part of the Gospel of John, should be regarded as an authentic tradition about Jesus. It could well be that it is ancient and may indeed represent an unusual instance where such a tradition survived outside of the bounds of the canonical literature. However, even that needs to be nuanced (see B. D. Ehrman, "Jesus and the Adulteress," NTS 34 [1988]: 24-44).
sn Double brackets have been placed around this passage to indicate that most likely it was not part of the original text of the Gospel of John. In spite of this, the passage has an important role in the history of the transmission of the text, so it has been included in the translation.