‘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 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 name?” Then I will declare to them, “I never knew you; go away from me, you evildoers.”
‘Everyone then who hears these words of mine and acts on them will be like a wise man who built his house on rock. The rain fell, the floods came, and the winds blew and beat on that house, but it did not fall, because it had been founded on rock. And everyone who hears these words of mine and does not act on them will be like a foolish man who built his house on sand. The rain fell, and the floods came, and the winds blew and beat against that house, and it fell—and great was its fall!’
Now when Jesus had finished saying these things, the crowds were astounded at his teaching, for he taught them as one having authority, and not as their scribes.
- Matthew 7:15-29
This passage from Matthew comes near the end of the preaching of the Sermon on the Mount. So I think we have to start with the framework of what it means to seek the will of the Father and to do the Father's will. The Sermon on the Mount is couched from the beginning in the "logic" of the kingdom: what it is to be what God likes and to live as a person in this kingdom, to seek that will. And perhaps most significantly, to live a life of prayer and communion with God which connects us to that "logic." It is in this Sermon, earlier, that Jesus gives us The Lord's Prayer.
But this passage in particular is concerned with those things that are not of the kingdom, and Jesus is warning us of those who will present themselves as a part of the kingdom and are deceivers. I quite like the analogy of sheep and wolves; after all, Jesus has called himself the Good Shepherd. But a ravening wolf is quite a good analogy for the selfish and those who wish to exploit followers. I don't know what can be worse than to be exploited by false spiritual teachers, or by those who use religion or spirituality to exploit others, and for their own sense of power and control. We must be wary of corruption and exploitation in many forms. It is important to me that Jesus does not exempt the fact that his own name will be used in this way. It is a warning to all of us that we do not live in a perfect world, and that this kingdom requires of us discernment.
Furthermore, those who claim to do work in Jesus' name and yet are not sincere in seeking the Father's will for that work will not be welcome. This kingdom is not about declaring oneself a follower and then deciding, separately from honest seeking, what exactly the logic of that kingdom must be, and what is to be done. Jesus even claims that there will be deeds of power, such as prophecy and casting out demons and more, which will be claimed to have been done in his name - but he will not recognize these people who are false in their hearts in his own kingdom.
So the great teaching comes down to what it is that we have inside of us; are we sincere? Do we sincerely seek that which God wills for us? What is our prayer life like and do we seek to be what God wants us to be? What kind of person are we willing to become, as we are shaped in life in communion? I think, taking this passage into context, this is what Jesus asks us. And it's also the basis for stern warnings, both to the faithful and to the false. He is the true vine - the false trees will not stand.
As always, he teaches as one with authority, and this stuns the crowds. The sincere will hear the message. His kingdom is the kingdom of the heart. I think he is asking us to be alert to what is in our hearts, and the fruits the heart produces - both the good and the bad.
Blessed are the pure in heart, for they shall see God.