The passage
      v13-14. The imagery of the two ways is vague and leads to a variety of translations. The NIV is best. There is a wide gate and we may enter it and travel on a broad way, but it leads to destruction. There is a small gate, followed by a narrow (not necessarily straight) way, and this way leads to life. Sadly, few enter the narrow gate. Jesus calls for decision, but what is the decision? The term for "narrow" in v14 often refers to persecution. Thus, the narrow way may image cross-bearing discipleship and the broad way that of compromised commitment. Yet, Jesus is not calling on us to press along the narrow way, but rather choose the small gate that leads to the narrow way. This gate leads to salvation and so is best understood as the small gate of obedience.
      v15. The imagery of the two trees, v15-20, is also a bit of a mystery, but makes much the same point as the two ways. Who are the false prophets? Thy are probably Pharisees/legalists, those who rest on a law-righteousness that leads to destruction. Their "fruit" gives them away, for like all rebels they are sinners. They "strain out gnats, but swallow camels", ie. they redesign the law so that it seems as if they keep it, but all they keep is "insect law" while ignoring justice, love, compassion, mercy.....
      v16-20. The berries of the buckthorn may look like little grapes, but are worthless fruit. A life that fails to produce the fruit of obedience will inevitably face the "fire".
      v21-23. The two claims represent those who are truly righteous and those who claim to be righteous (law obedient). Those who share in eternity do "the will of my Father who is in heaven." Those who are cast out may perform righteous and worthy deeds, but they are ultimately deemed "evildoers."
      v24-27. Finally, the two builders sum up two ways - the way of perfect righteousness and the way of self-righteousness. On the day of judgement one will stand and one will fall. "The will of my Father who is in heaven", v21, now becomes "these words of mine." The wise man is he who "hears these words" and "puts them into practice." That is, does exceeding righteousness - perfectly obeys. If "these words of mine" are not "put into practice" then the future involves a "great crash." So, Jesus again illustrates the truth that "no one is good except God alone". We have all built our house on the sand and face destruction. We are left with the question, how then can we survive the "great crash"?
      v28-29. The crowd is "amazed" - a response far from faith. They are astonished at his "authority", ie. he declares God's truth on his own authority, unlike the prophets who say "Thus says the Lord."

The way of faith
      The Pharisees saw Jesus as a libertine. He associated with unclean people, cared little about Sabbath Day regulations and came "eating and drinking." They even called him "a wine bibber and a glutton." Jesus, on the other hand, said he had not "come to abolish the Law and the Prophets." In fact, he came "to fulfill them." By "fulfill" he meant "complete". When it comes to the Law, he taught a righteousness that exceeds that of the Pharisees and the teachers of the Law. In fact, said Jesus, we "will certainly not enter the kingdom of heaven" if we fall short of the law-obedience revealed in the Sermon on the Mount. The Mosaic Law may permit "an eye for an eye", but Jesus teaches that perfect righteousness demands that we "do not resist an evil person." The Mosaic Law may denounce murder, but Jesus teaches that perfect righteousness demands a life free from anger.
      At the end of the sermon, Jesus calls for self examination. Which gate have we entered, which tree represents us, which claim do we make, which house-builder represents us? Does our law-obedience, either before or after our conversion (even our baptism in the Spirit), in any way get us through the narrow gate, keep us on the narrow way, make us a fruitful tree, support our claim before God, or somehow build our house on rock? The answer is no, for our righteousness is always filthy rages; we have all sinned (and have continued to sin) and fallen short of the glory of God. Who then will rescue us from the "great crash"?
      There is one who has entered the narrow gate, whose fruit is pure and whose house is firmly on the rock. He has done the will of the Father. Those who identify with this righteous Jew, who hold onto his tassels as he enters the gates of the heavenly city and presents himself before the Ancient of Days, are graciously treated as if they were this righteous man. So, our task is a simple one. We must seek out the house of this righteous man, knock on his door and ask to come in and there to find rest for our soul. The good news is "ask and it will be given you, seek and you will find, knock and the door will be opened. For everyone who asks receives, he who seeks finds, and to him who knocks the door will be opened", Matt.7:7-11.

1. The purpose of the Law
      If it is true that our righteousness must exceed that of the Pharisees and the Teachers of the law for us to enter the kingdom of Heaven, 5:20, then obviously few will enter. If only those who do the will of the Father enter the kingdom of Heaven, 7:21, then none of us will enter. There are none who hear the words of Jesus and put them into practice, 7:24. So what is the function of this new law proclaimed by Jesus?
      The apostle tells us that our eternal right standing in the sight of God is gained and maintained apart from works of the law (ie. apart from Law-obedience). The law that Paul is addressing is the moral law in all its perfection. The prime function of this law is to expose sin and drive us to Christ for mercy, Gal.3:24. Once it has fulfilled this role, it returns to the more menial task of giving direction to the renewing work of the Holy Spirit, a work that progresses by grace through faith and not works of the law. Paul's radical theology is not of his own making, it came from Jesus. One obvious source is the Sermon on the Mount. In the sermon Jesus gives us a detailed exposition of the law which removes any possibility of anyone ever claiming to have done it. Few people will ever commit murder, but we all get "angry with a brother" sooner or later.
      So, the Sermon on the Mount, as an exposition on the substance of the moral law, serves to expose our state of sin and so drive us to God for mercy. We are being told, in no uncertain terms, that we have built our house on the sand and therefore face the destruction of coming judgment. Only in the shadow of the cross will we find safety.

2. The standing of a believer
      In the illustrations of the two ways, two trees, two claims and two builders, Jesus clearly links the sinner (with special reference to the self-righteous sinner) to the broad way, the bad tree, no claim and sand foundations. We are all in the same boat, facing the same end. So, as noted above, the sermon concludes with its prime function clearly in sight, namely, to expose our state of loss and so drive us to God for mercy.
      Yet, as we know well, these illustrations are often applied to the Christian life. For example, we are told that when we believe in Jesus we enter the narrow gate and travel the narrow road. The danger we face is that we may slip off the narrow road onto the wide road that leads to destruction (of course, a reformed interpretation would argue that the gate determines the way). In the old Sunday School chorus we are urged to build on the rock and not upon the sand so that our house will stand the thunder clap. A person will survive the day of judgement if they build their life on the person and work of Christ rather than on their own good works. A sentiment that is true, but not derived from this passage
      If we want to be true to scripture we should let the illustrations serve their intended end. They proclaim that we travel the broad way, produce bad fruit, have no claim before God, and build our house on sand. Remember, these words are primarily for disciples, believers, 5:1-2. As the apostle constantly reminds us, we are justified by grace through faith and not works of the law. We have no claim to right standing apart from the cross and the empty tomb. When we stress travelling the narrow road or building on the rock, we convey a false implication - that by our faithful obedience we maintain and progress our Christian standing, when of course our standing before God is wholly of grace appropriated through faith.
      As can be noted in the summary sermon above, I do take some liberties with the illustrations, extending them beyond their intended purpose. The reason, of course, is simple. I find it difficult to leave a congregation in despair, particularly when I am convinced Jesus would not leave anyone in despair. Note how, in the Sermon on the Mount, Jesus provides a way of escape from the condemnation of the law, 5:1-10 (it is those who hunger and thirst for righteousness who are filled), 7:7-11 (the way forward is to ask, seek and knock). So, we are bound to develop the illustrations using the doctrine of justification.
      "There is now no condemnation for those who are in Christ Jesus", Rom.8:1. By means of our identification with Christ we no longer face eternal condemnation because in the sight of God we are now regarded and treated as if we are an obedient Son of God. The instrument of this gift of grace is faith - faith in Christ. Therefore, the means of gaining our eternal right-standing in the sight of God is by grace through faith.
      Thus, although we don't enter the narrow gate, produce the good fruit, make the just claim and build on the rock, Christ, the one righteous son of God, on our behalf has. In our identification with him, by grace through faith, we are treated as if we are a righteous son of God. We may be on the broad road that leads to destruction, but by grace through faith we are viewed by God as if we are on the narrow road that leads to life. Our house may be on sand, about to collapse, but by grace through faith we are viewed by God as if it were on rock. The Father counts Christ's house, not ours, Christ's life, not ours.
      So, where is our house built? Yes, it is built on the sand (the old Adam awaiting the grave), but as far as that awful day is concerned and the glory that lies beyond, we are invited guests in Christ's house, and his house will stand against that day.

      As a sub note the reader might have observed how the extension of the illustrations highlights the law-grace debate. If we are secure in Christ's house, why bother working on our own? Of course, Paul, the exponent of free grace, wrestled with this same problem, even the absurd "shall we go on sinning that grace may increase?" Why not turn our house into a bordello if we are secure in Christ's house? The more filthy our house, the more gracious the invite to Christ's house. Paul's answer is simple enough, "we died to sin, how can we live in it any longer?" It is inconceivable that a person who is welcomed into Christ's house would not want their house to at least image, in part, the beauty of Christ's construction on the rock.

Greek notes

v13
      stenhV "narrow" - Possibly "difficult", in the same way "broad" may be "easy".

v14
      teqlimmenh (qlibw) perf. pass. part. "small" - Narrow and confined and therefore possibly "hurtful" (persecution?).

v15
      arpageV (arpax) "ferocious" - greedy, raging, ravenous.

v16
      epignwsesqe (epiginwskw) fut. ind. mid. "recognize" - know.

v17
      sapron "bad" - decayed or rotten.

v22
      erousin (legw) fut. ind. act. "will say"
      eprofhteusamen (profhteuw) "prophesy" - speak on behalf of another. Here, speaking on behalf of Jesus.

v23
      oJmologhsw (oJmologew) "I will tell ... plainly" - I will declare, proclaim, make a statement..... which is binding.
      oudepote egnwn (ginwskw) uJmas "I never knew you" - These words were used by the rabbis for an excommunication.
      onmian "evildoers" - without the law, lawlessness. More particularly, lax law-keeping.

v24
      poiei (poiew) "puts .... into practice" - does, applies. Hears the words of Jesus and acts on them.
      oJmoiwqhsetai (omiow) "is like" - will be like, likened, compared. In the last day the person who hears the words of Jesus and does them will be like the wise person who has built their house on rock.

v25
      katebh (katabainw) "came down" - fell down
      potamoi "streams rose" - Used to describe flooded ravines after rain.

v26
      mwpw/ "foolish" - unreflecting. Someone who doesn't think through the consequence of their actions.