Many commentators reject John 7:53-8:11, echoing Bruce Metzger’s well-known comments in different ways. The NET, for example, states that this passage (the passage about the adulteress, also called the pericope adulterae) “is not contained in the earliest and best MSSand was almost certainly not an original part of the Gospel…

via Early Latin Evidence for John 7:53-8:11 — The Text of the Gospels