Bruce Metzger and Bart Ehrman. The picture is of Luke 11:2 and it is from Codex Sinaiticus (compiled around 330-360 CE, generally).
Various modern English translations confirm in footnotes that John
7:53-8:11 is an interpolation. The CEB notes that “critical editions of
the Gk New Testament do not contain 7:53-8:11” and the NRSV supports
this with “most ancient authorities lack 7.53—8.11; other authorities
add the passage here or after 7.36 or after 21.25 or after Luke 21.38,
with variations of text; some mark the passage as doubtful.” Metzger
explains that John’s pericope is missing from the “most early and
diverse manuscripts” (Metzger, 187). There are external factors besides
its manuscript omission: early church fathers don’t quote it until the
twelfth century, showing a lack of awareness of the text in question
(Metzger, 188) and that it also appears in multiple locations through
John’s Gospel as the NRSV footnote states. This shows that scribes were
uncertain about its placement within the narrative.
The text’s addition may have been due to a scribe’s belief in the truthfulness of the account, and because of this they had little issue in trying to place it within the narrative. Coupled with this, the story is moving and shows Jesus in a consistent and compassionate light (c.f. his interactions with the unmarried Samaritan woman in John 4). After all, Metzger acknowledges, “the account has all the earmarks of historical veracity” (Metzger, 188) as a self-contained story. It may have happened, but John in his original Gospel did not include it.
In explaining this text, a minister must be careful to gently articulate the problems. Text-criticism is a highly specialized field, and requires precision and clarity in explaining the various complexities of the issue. Part of the issue may involve the long, steady process of educating a congregation. It is not as simple as ignoring an issue, especially in an age of Internet experts and popular level works from Barth Ehrman. Educating the congregation would establish a base in the more conservative areas of the Christian family, especially since there are many conservative textual scholars (c.f. Bruce Metzger and Philip Barton Payne) who have not abandoned their faith.
As for preaching this text, one again has to be careful not to overstress historical critical issues to a congregation, for fear of undermining one’s faith. A pastor has several options: she could mention the text critical aspects of this text by pointing to the footnotes in the Bible and suggest that these issues could be covered in greater detail in an adult bible study apart from the main sermon. Some pastors—such as Greg Boyd—do video blogs after their sermons on the more technical aspects of the text. I would personally have no problem preaching from John 7:53-8:11, provided my congregation was aware of the issues within the text, and I would happily explain it in greater detail on the side to anyone interested. Scripture is, after all, an open book and all great and inspired books have history.