The Gnosticism that St. Irenaeus of Lyons challenged in his classic work “Against Heresies” was confusing for a number of reasons. Among other things, the Gnostics had complicated formulas for interpreting different numbers that appear in the Gospel.

St. Irenaeus warns against this kind of approach to Scripture, because of its selective nature; it comes to the Gospels with a preconceived notion, and then seeks out passages that affirm that, and ignores passages that don’t support it.