4 But your wife comes to you advising you to some evil thing. Thou dost love her as a wife should be loved; she is one of your members. “But if your eye offend you, if your hand offend you, if your foot offend you,” you have just heard the Gospel, “cut them off, and cast them from you.” Whosoever he be that is dear to you, whosoever he be that is held in high estimation by you, let him be so long of high esteem with you, so long your beloved member, as he shall not begin to offend you, that is, to advise you to any evil.
Hear now how that this is the meaning of “offense.” I have brought forward the example of Job and his wife; but there the word “offense” did not occur. Hear the Gospel: when the Lord prophesied of His Passion, Peter began to persuade him not to suffer. “Get behind Me, Satan, you are an offense to Me.” Here undoubtedly the Lord who has given you an example of life, has taught you both what an “offense” is, and how an offense is to be avoided. Him to whom He had a little while before said, “Blessed are you, Simon Bar-jona;” He had shown to be His member.
But when he begins to be an offense, He cuts off the member; only He restored the member, and put it into its place again. He then will be an “offense” to you, who shall begin to persuade you to any evil thing. And here, Beloved, take heed; this takes place for the most part not through any evil will, but through a mistaken good will. Your friend who loves you, and is loved by you again, your father, your brother, your child, your wife, sees you in an evil case, and would have you do what is evil.
What do I mean by “sees you in an evil case”? Sees you in some press of trouble. This pressure it may be you are suffering for righteousness' sake; art suffering it because you will not give false witness. I would speak merely by way of illustration. Examples abound; for “woe to the world, because of offenses.” See, for instance, some powerful person, to cover his rapine and plunder, asks of you the service of a false witness. You refuse: refuse the false oath, lest you should deny Him that is true.
That I may not dwell long on this, he is angry, he is powerful, he oppresses you: a friend comes who would not have you in this press of trouble, in this evil case; “I pray you, do what is told you; what great matter is it?” And then perhaps as Satan with the Lord, “It is written of You, He shall give His Angels charge concerning You, that Thou dash not Your foot against a stone.” Perhaps too this friend of yours, because he sees you are a Christian, wishes to persuade you out of the Law to do what he thinks you ought to do.
“Do what the other tells.” “What? Do what the other wishes.” “But it is a lie, it is false.” “Well, have you not read, 'All men are liar.'?” Now is he an “offense.” He is a friend, what will you do? He is an eye, he is a hand: “Cut it off, and cast it from you.” What is, “cut it off, and cast it from you”? Consent not to him. For members in our body make up unity by consent, by consent they live, by consent are joined together one with the other. Where there is dissent, there is disease, or a sore. He is then one of your members; you will love him. But he is an offense to you; “Cut him off, and cast him from you.” Consent not to him; drive him off from your ears, it may be he will return amended.
Source: Sermons on Selected Lessons of the New Testament (New Advent)