"Beware of false prophets, who come to you in sheep's clothing but inwardly are ravenous wolves. You will know them by their fruits. Are grapes gathered from thorns, or figs from thistles? In the same way, every good tree bears good fruit, but the bad tree bears bad fruit. A good tree cannot bear bad fruit, nor can a bad tree bear good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. Thus you will know them by their fruits.
Not everyone who says to me, 'Lord,Lord,' will enter the kingdom of heaven, but only the one who does the will of my Father in heaven. On that day many will say to me, 'Lord, Lord did we not prophesy in your name, and cast out demons in your name, and do many deeds of power in your power?' Then I will declare to them, 'I never knew you; go away from me, you evil-doers.'" (Matthew 7:15-23) (NRSV)
What are we to make of these two related yet distinct scripture paragraphs? Both look ahead in time to a movement or community after Jesus. While well respected scholars often ascribe such passages to the early church rather than Jesus, I think it reasonable to assign Matthew 7:15-23 to him. With due respect to those who prefer to restrict Jesus' perspective to the apocalyptic, I find him to have been more complex. In particular, he often seems to have anticipated that a community would develop in his aftermath. Such a community, while informed by his teachings and life, would be subject to the dangers of deception and self-deception. It seems to me Matthew 7:15-23 addresses these matters.
Many a modern tale and animated feature has drawn on the image of the wolf in sheep's clothing. In the passage, the core message is to beware of would-be leaders who claim to follow the Good Shepherd but who actually aim to ravage and fleece the flock! I can't speak to Jewish history, but Christian history provides numerous examples of sheep-skin wearing wolves. Some sought to divorce Christianity from its Jewish roots by discarding the Hebrew Bible (or the Hebrew Bible as mediated through the LXX). Others pushed forms of antinomianism, gnosticism (no matter how ill defined the term), expanded membership requirements, and the like. In recent centuries false teachers have tried to lead the Christian movement to endorse slavery, racism, discrimination, sexism, greed,preemptive war, and torture. Both of us could cite numerous specific examples. The end results (the fruits) are division, pain, suffering and death for many--a fracturing of the community of the human race, and the subversion of the church.
Jesus indicates we need never let matters go so far. If the church will practice a kind of tough vigilence, it may discern the fruits of false leaders and move to stem the damage. It's interesting to me that Jesus assigns the community and those within it the responsiblity for discernment. We are to tend our own fruit grove!
Self-deception also poses an ongoing threat. Verses 21-22 speak of the all too human tendency to confuse lip service with reality. "Lord," of course, became part of the earliest Christian confession, by which one not only signaled one's commitment to follow Jesus but also one's entry into the Christian community. Here Jesus gives clear warning against reliance on confessional or other religous language. Such language, while useful, must line up with one's inner orientation, or it means nothing.
In like fashion, good deeds, such as the two examples of inspired preaching and exorcism, may or may not reveal a genuine commitment to God. Something more is needed: alignment with God. The Sermon on the Mount captures much of what that might be. I suspect 1 Corinthians 13 does as well.