Chapter 7:24-29 The Two Foundations

7:24 Therefore whosoever heareth these sayings of Mine, and doeth them, I will liken him unto a wise man, which built his house upon a rock:

Therefore whosoever heareth these sayings of Mine - That is, the excellent doctrines laid down before in this and the two preceding chapters. 

7:25 And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell not: for it was founded upon a rock.
Whoever you are, and whatever you build, it will be tried. No matter how firm is the rock beneath you, the winds will blow, and the rains will pour down upon your building. Whether you are in a palace or in a hovel, trial and testing must and will come to you: “The floods came, and the winds blew, and beat upon that house,-

7:26 And every one that heareth these sayings of Mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand:

And every one that heareth - and doeth them not - Was there ever a stricter system of morality delivered by God to man, than in this sermon? 

He who reads or hears it, and does not look to God to conform his soul and life to it, and notwithstanding is hoping to enter into the kingdom of heaven, is like the fool who built his house on the sand. When the rain, the rivers, and the winds come, his building must fall, and his soul be crushed into the nethermost pit by its ruins. 

7:27 And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it.
And the rain descended, and the floods came - Such builders, and such a building, cannot stand against the violent rain of Satan's temptations, the floods of the world's persecutions, the stream and rapid torrent of their own heart's lusts, nor the blowing winds of heresy and false doctrine, and much less the storms of divine wrath and vengeance. 

They are in a most dangerous condition; they cannot support themselves; they must fall, and great will be their fall; their destruction is inevitable, their ruin is irrecoverable.

7:28 And it came to pass, when Jesus had ended these sayings, the people were astonished at His doctrine:
The people were astonished at His doctrine; it being something new, and unheard of, what they had not been used to; and coming in the demonstration of the Spirit, and of power, it carried its own evidence along with it, wrought conviction in their minds, and obliged them to acknowledge the truth of it.

7:29 For He taught them as one having authority, and not as the scribes.

Having authority - They felt a commanding power and authority in His word, i.e. His doctrine.

Chapter 7:15-23 A Tree and Its Fruit

7: 15 Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.
Beware of false prophets - teachers of erroneous doctrines, who come professing a commission from God, but whose aim is not to bring the heavenly treasure to the people, but rather to rob them of their earthly good. 

In sheep's clothing - With outside religion and fair professions of love: 

Wolves - Not feeding, but destroying souls.

7:16 Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?
The illustration of this comparison, of the fruit's being the discovery of the tree. You cannot always distinguish them by their bark and leaves, nor by the spreading of their boughs, but by their fruits ye shall know them. 

The fruit is according to the tree. Men may, in their professions, put a force upon their nature, and contradict their inward principles, but the stream and bent of their practices will agree with them. Christ insists upon this, the agreeableness between the fruit and the tree, which is such as that, if you know what the tree is, you may know what fruit to expect. Never look to gather grapes from thorns, nor figs from thistles; it is not in their nature to produce such fruits.

7:17 Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit.

So every good tree - As the thorn can only produce thorns, not grapes; and the thistle, not figs, but prickles; so an unregenerate heart will produce fruits of degeneracy. 

A man cannot be a saint and a sinner at the same time. 

Let us remember, that as the good tree means a good heart, and the good fruit, a holy life.

7:18 A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.

A good tree cannot bring forth evil fruit - A man that is unprincipled with the grace of God, has an experimental acquaintance with the Gospel of Christ, and is guided by the Spirit of God into all truth, as it is in Jesus, cannot knowingly deliver, maintain, and abide by any doctrine that is contrary to the glory of God's grace, and the person of Christ, the work of the Spirit, the fundamental doctrines of the Bible; or what is repugnant to the experiences of God's people, and prejudicial to their souls.
Neither can a corrupt tree bring forth good fruit - A corrupt preacher, one destitute of the truth of the Gospel, reprobate concerning the faith, who never had any experience of the doctrines of grace, and denies them in the theory of them, cannot, consistent with himself, and his own principles, deliver, or preach good doctrine; or that which tends to produce any good fruit, either in the experience or lives of men.

7:19 Every tree that bringeth not forth good fruit is hewn down, and cast into the fire.

How dreadful then is the condition of that teacher who hath brought no sinners to God!

7:20 Wherefore by their fruits ye shall know them.

This is the conclusion of the whole, and a repetition of what is before said, the more to fix the rule of judgment upon their minds, and engage them to try men by their doctrines, and their doctrines by the standard of the Scriptures, and not believe every spirit; for with some care and diligence such persons may be detected, and the malignant influence of their ministry be prevented.

7:21 Not every one that saith unto Me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of My Father which is in heaven.

It is an answer to that question, Psalm 15:1. Who shall sojourn in thy tabernacle? - the church militant; and who shall dwell in thy holy hill? - the church triumphant.

7:22 Many will say to Me in that day, Lord, Lord, have we not prophesied in Thy name? and in Thy name have cast out devils? and in Thy name done many wonderful works?

We have prophesied - We have declared the mysteries of Thy kingdom, wrote books; preached excellent sermons: In Thy name done many wonderful works - So that even the working of miracles is no proof that a man has saving faith.

7:23 And then will I profess unto them, I never knew you: depart from Me, ye that work iniquity.

Then will I profess unto them - Publicly before men and angels, at the day of judgment.
I never knew you - which must be understood consistent with the omniscience of Christ; for as the omniscient God He knew their persons and their works, and that they were workers of iniquity; He knew what they had been doing all their days under the guise of religion; He knew the principles of all their actions, and the views they had in all they did; nothing is hid from Him.
Depart from Me - What a terrible word! What a dreadful separation!