Paul notes in 2 Corinthians 11:12-15 that some in the first-century church were not faithful in their teaching, not honest in their motives, and not open about their intentions, when they presented themselves to the Corinthian Christians as teachers and “leaders.” Our world thrives on the notion that all beliefs and ideas (and therefore, all who present them) are equally valid and worthy of respect. Paul clearly did not subscribe to this opinion! In verse 12 he plainly states his intention is to “cut off” opportunities for such individuals to have any influence among the saints (the Greek word refers to cutting down a tree). He goes on to describe these self-proclaimed “apostles” as false apostles and deceitful workers (vs. 13), who “disguise” themselves as apostles of light! These sound like harsh words in today’s world, but the people Paul describes here were fundamentally dishonest – liars, presenting a fraudulent version of the gospel in order to gain influence and a following for themselves among the Corinthian Christians. Paul goes on to say that they were disciples of Satan for following his methods (disguising themselves as “ministers of righteousness” when they were not – note also Jesus’ words in Matthew 7:15).
What we should understand in reading these verses is that the motives, methods, and character of false brethren have not changed in the twenty-first century. The gospel is still the only measure of a person’s faithfulness and acceptability to the Lord. No degree of personal popularity can excuse an “uncertain sound” (1 Corinthians 14:8) or a false gospel. As Paul pointed out so vividly in 2 Corinthians 6:14-16, truth and righteousness have no common ground with lies and unrighteousness.
Paul’s mention of a “thorn in the flesh” in 2 Corinthians 12:7-10 has led many to speculate about what it actually was. Various commentators have suggested everything from poor eyesight to crippling shyness to epileptic seizures. Nothing in the text actually explains “what” the “thorn” was, so we have no way to say definitively. What actually matters (and should interest us) is that Paul described it as a messenger (literally, an “angel”) of Satan. He also says it was imposed on him to prevent him from being egotistical or conceited about the revelations God had allowed him to see (vv. 2-6). Christians need to understand that faithfulness to the Lord does not “guarantee” that we will no longer have troubles or trials in this life. Rather, difficulties test our willingness to trust in depend on the Lord (“My grace is sufficient…” vs. 9), in order to grow stronger in the faith.
One of Paul’s final instructions (in 13:5) relates to the previous point; as Christians, we need to “test” ourselves against the gospel. The words “examine” and “prove” (KJV) in this verse are actually legal terms that describe “putting oneself on trial” to make sure we “measure up” to the gospel’s ideal. God’s people are supposed to “know” ourselves thoroughly because of the presence and influence of Jesus Christ within us (cf. John 6:56; Colossians 1:27). In Ephesians 3:16, Paul shows the “how” of Christ’s dwelling within us – by means of faith. The alternative to Christ’s presence in our lives is for us to be “reprobates,” those who have not “passed the test!” In other words, we are supposed to conduct a sort of “personal inventory” or review – a self-examination to find and correct whatever we must, while we have the opportunity! This way, we can be sure we do measure up to our Lord’s standard (vv. 6-7).