It turns out that the whole concept, and specific quotes, were taken from a homily by St. Chromatius of Aquileia.  (Tractatus LVI, on Matthew 18:8-9.) The bishop was very powerful and famous at the time (his diocese stretched from parts of Italy all the way to Bavaria, and lots of famous people wrote him letters). He had to deal with a lot of dissent, including Arianism. It’s pretty obvious that St. Isidore and St. Beatus of Liebana were familiar with this homily (including exact quotes), but it was essentially lost to us until  a big batch more of his Matthew sermons were found in 1969. I’ll translate the homily later over on my blog, because it’s very good, but here’s the gist.

Of course the congregation had just finished hearing the Gospel passage, so the good bishop quotes pretty sparingly and gradually. The full verses are: “And if thy hand or thy foot scandalize thee, cut it off, and cast it from thee. It is better for thee to go into life maimed or lame, than having two hands or two feet, to be cast into everlasting fire. And if thy eye scandalize thee, pluck it out, and cast it from thee. It is better for thee having one eye to enter into life, than having two eyes to be cast into hellfire.” He explains that this doesn’t mean actual body parts (and that people who lose actual body parts don’t stop sinning!), but rather to evil thoughts and longings of one’s heart and soul, which lead to scandal and evil unless you amputate them.

But in another way, they refer to those in charge of the Church, because the Church is the (mystical) Body of Christ. He quotes a pre-Vulgate, Old Latin version of 1 Corinthians 12:25-27, right in the midst of the talk about the Body and the members’ different gifts: “That there might be no separations [separationes] in the body; but the members might be mutually careful one for another.  And if one member suffer anything, all the members suffer with it; or if one member is honored [honorificatur], all the members rejoice with it. Now you are the Body of Christ, and members from out of a member.” So if all of us are body parts, all of us can be cut off if need be. (Which is sort of a warning today to the “no hands but ours” crowd, when you think about it….)

“And so we understand “the hand” to signify priests, whose works for all are as necessary as a hand to the body of the Church. Of which we find it written in the Song of Songs, “His hands” — that is, those of the body of the Church — “are turned, golden, full of hyacinths.” (Songs 5:14, more Old Latin version)

“And we recognize deacons signified in “the foot”, those who will be run around in the sacred Mysteries of the Church [ie, the Sacraments]; they serve just like feet of the body. Of which we read, written by the same Solomon, “His feet are like silvery columns set upon golden bases.” (Songs 5:15, more Old Latin.)

“And so in this way, if the hands or feet — that is, the priest or deacon — should have made a scandal of the Church, either through crooked faith or through a wrong way of life, the Lord commands that such a man be cut off from the body of the Church, lest the whole body be endangered by scandal and unfaithfulness.”

And then he quotes 1 Cor. 5:6 and 6:16.

Next, he moves to bishops being signified by “the eye,” opining that the bishop should be more like Songs 5: 12 (“Eyes like doves”)  and less like the kind that needs plucking out. He goes pretty strongly into the danger of having a bad teacher in charge of a diocese. (St. Chromatius lived in a time of many heresies promulgated by bad bishops, especially Arianism.)

Then he quotes 1 Cor. 5:6-7 and 5:13 as action items, John 12:26 as a reassurance to good clergy, and Wis. 6:7 and 9 as a warning to bad clergy. And that’s it. It’s about two and a half pages and probably was preached pretty briskly.

It’s kind of a pity that more people didn’t listen to St. Chromatius in 1969 and following. He’s very practical and firm.