Why did we at Trinity not preach on John 7:53-8:11, which covers the famous scene of the woman caught in adultery?

The reason is pretty simple: both the external and the internal evidence overwhelming show that this passage was not original to the author John.

External Evidence

The earliest and best manuscripts, from which modern English bibles are translated, simply do not include this section. The earliest Greek manuscript known to contain the pericope is codex Bezae (D), which is from the fifth or sixth century. Furthermore, no Greek Church Father comments on this passage until the twelfth century (Euthymius Zigabenus).

Internal Evidence

The narrative ending in John 7:52 flows much more naturally into 8:12. This is likely one reason why John 7:53-8:11 appears in later manuscripts in several different places in John’s gospel account. Additionally, the vocabulary and grammar used in the pericope seem foreign to John, with 14 out of 82 vocabulary words found nowhere but in this pericope.

In Conclusion

At Trinity we are committed to preaching God’s word in its entirety, as originally inspired by the Holy Spirit, as spoke of in the Westminster Confession of Faith (1.8):

The Old Testament in Hebrew (which was the native language of the people of God of old), and the New Testament in Greek (which, at the time of the writing of it was most generally known to the nations), being immediately inspired by God, and, by His singular care and providence, kept pure in all ages, are therefore authentical; so as, in all controversies of religion, the Church is finally to appeal unto them.

Therefore, our commitment is to what is often called the “autograph,” the original account composed by each author in scripture. While none of these autographs exist today, scholars use textual criticism (i.e., using external and internal evidence) to the best of their ability in order to determine what was contained in the “autograph.” Since this pericope was clearly not in John’s autograph, we chose to move forward to John 8:12-30.

For more reading on this, see:

Bruce Metzger, A Textual Commentary on the Greek New Testament.

Bruce Metzger, The New Testament: Its Background Growth and Content

Harvie Conn, ed., Inerrancy and Hermeneutic

Additionally, see this helpful “cheat sheet” from Austin Bible Church.