Here the apostle informs us what foundation he had laid at the bottom of all his labours among them - even Jesus Christ, the chief corner-stone, Eph 2:20. Upon this foundation all the faithful ministers of Christ build. Upon this rock all the Christians found their hopes. Those that build their hopes of heaven on any other foundation build upon the sand. Other foundation can no man lay besides what is laid - even Jesus Christ. Note, The doctrine of our Saviour and his mediation is the principal doctrine of Christianity. It lies at the bottom, and is the foundation, of all the rest. Leave out this, and you lay waste all our comforts, and leave no foundation for our hopes as sinners. It is in Christ only that God is reconciling a sinful world to himself, Co2 5:19. But of those that hold the foundation, and embrace the general doctrine of Christ's being the mediator between God and man, there are two sorts: -

I.Some build upon this foundation gold, silver, and precious stones (Co1 3:12), namely, those who receive and propagate the pure truths of the gospel, who hold nothing but the truth as it is in Jesus, and preach nothing else. This is building well upon a good foundation, making all of apiece, when ministers not only depend upon Christ as the great prophet of the church, and take him for their guide and infallible teacher, but receive and spread the doctrines he taught, in their purity, without any corrupt mixtures, without adding or diminishing.

II.Others build wood, hay, and stubble, on this foundation; that is, though they adhere to the foundation, they depart from the mind of Christ in many particulars, substitute their own fancies and inventions in the room of his doctrines and institutions, and build upon the good foundation what will not abide the test when the day of trial shall come, and the fire must make it manifest, as wood, hay, and stubble, will not bear the trial by fire, but must be consumed in it. There is a time coming when a discovery will be made of what men have built on this foundation: Every man's work shall be made manifest, shall be laid open to view, to his own view and that of others. Some may, in the simplicity of their hearts, build wood and stubble on the good foundation, and know not, all the while, what they have been doing; but in the day of the Lord their own conduct shall appear to them in its proper light. Every man's work shall be made manifest to himself, and made manifest to others, both those that have been misled by him and those that have escaped his errors. Now we may be mistaken in ourselves and others; but there is a day coming that will cure all our mistakes, and show us ourselves, and show us our actions in the true light, without covering or disguise: For the day shall declare it (that is, every man's work), because it shall be revealed by fire; and the fire shall try every man's work, of what sort it is, Co1 3:13. The day shall declare and make it manifest, the last day, the great day of trial; see Co1 4:5. Though some understand it of the time when the Jewish nation was destroyed and their constitution thereby abolished, when the superstructure which judaizing teachers would have raised on the Christian foundation was manifested to be no better than hay and stubble, that would not bear the trial. The expression carries in it a plain allusion to the refiner's art, in which the fire separates and distinguishes the dross from the gold and silver; as it also will silver and gold and precious stones, that will endure the fire, from wood and hay and stubble, that will be consumed in it. Note, There is a day coming that will as nicely distinguish one man from another, and one man's work from another's, as the fire distinguishes gold from dross, or metal that will bear the fire from other materials that will be consumed in it. In that day, 1. Some men's works will abide the trial - will be found standard. It will appear that they not only held the foundation, but that they built regularly and well upon it - that they laid on proper materials, and in due form and order. The foundation and the superstructure were all of a piece. The foundation-truths, and those that had a manifest connection with them, were taught together. It may not be so easy to discern this connection now, nor know what works will abide the trial then; but that day will make a full discovery. And such a builder shall not, cannot fail of a reward. He will have praise and honour in that day, and eternal recompence after it. Note, Fidelity in the ministers of Christ will meet with a full and ample reward in a future life. Those who spread true and pure religion in all the branches of it, and whose work will abide in the great day, shall receive a reward. And, Lord, how great! how much exceeding their deserts! 2. There are others whose works shall be burnt (Co1 3:15), whose corrupt opinions and doctrines, or vain inventions and usages in the worship of God, shall be discovered, disowned, and rejected, in that day - shall be first manifested to be corrupt, and then disapproved of God and rejected. Note, The great day will pluck off all disguises, and make things appear as they are: He whose work shall be burnt will suffer loss. If he have built upon the right foundation wood and hay and stubble, he will suffer loss. His weakness and corruption will be the lessening of his glory, though he may in the general have been an honest and an upright Christian. This part of his work will be lost, turning no way to his advantage, though he himself may be saved. Observe, Those who hold the foundation of Christianity, though they build hay, wood, and stubble, upon it, may be saved. This may help to enlarge our charity. We should not reprobate men for their weakness: for nothing will damn men but wickedness. He shall be saved, yet so as by fire, saved out of the fire. He himself shall be snatched out of that flame which will consume his work. This intimates that it will be difficult for those that corrupt and deprave Christianity to be saved. God will have no mercy on their works, though he may pluck them as brands out of the burning. On this passage of scripture the papists found their doctrine of purgatory, which is certainly hay and stubble: a doctrine never originally fetched from scripture, but invented in barbarous ages, to feed the avarice and ambition of the clergy, at the cost of those who would rather part with their money than their lusts, for the salvation of their souls. It can have no countenance from this text, (1.) Because this is plainly meant of a figurative fire, not of a real one: for what real fire can consume religious rites or doctrines? (2.) Because this fire is to try men's works, of what sort they are; but purgatory-fire is not for trial, not to bring men's actions to the test, but to punish for them. They are supposed to be venial sins, not satisfied for in this life, for which satisfaction must be made by suffering the fire of purgatory. (3.) Because this fire is to try every man's works, those of Paul and Apollos, as well as those of others. Now, no papists will have the front to say apostles must have passed through purgatory fires.

The day shall declare it, because it shall be revealed by fire - There is much difference of opinion relative to the meaning of the terms in this and the two following verses. That the apostle refers to the approaching destruction of Jerusalem I think very probable; and when this is considered, all the terms and metaphors will appear clear and consistent.

The day is the time of punishment coming on this disobedient and rebellious people. And this day being revealed by fire, points out the extreme rigour, and totally destructive nature, of that judgment.

And the fire shall try every man's work - If the apostle refers to the Judaizing teachers and their insinuations that the law, especially circumcision, was of eternal obligation; then the day of fire - the time of vengeance, which was at hand, would sufficiently disprove such assertions; as, in the judgment of God, the whole temple service should be destroyed; and the people, who fondly presumed on their permanence and stability, should be dispossessed of their land and scattered over the face of the whole earth. The difference of the Christian and Jewish systems should then be seen: the latter should be destroyed in that fiery day, and the former prevail more than ever.

Every man's work shall be made manifest,.... The doctrine he preaches shall be sooner or later made manifest to himself, and to his hearers; who shall see the inconsistency, irregularity, and deformity of such a building; at first so well laid, then piled up with such excellent materials, and at last covered in with such trifling or incoherent stuff:

for the day shall declare it; meaning not the day of judgment, though that is often called the day, or that day, and will be attended with fire, and in it all secrets shall be made manifest; but the apostle intends a discovery that will be made of doctrines in this world, before that time comes: wherefore this day rather designs a day of tribulation; as of persecution, which tries men's principles, whether they are solid or not; and of error and heresy, when men are put upon a re-examination of their doctrines, whereby persons and truths that are approved are made manifest; or of some great calamity, such as the destruction of Jerusalem, whereby many wrong notions the Jews yet retained were discovered: but it is best of all to understand this day of the Gospel day, and of the progress of Gospel light, especially in some particular periods of it; as in the primitive times, at the reformation from popery, and the more remarkable Gospel daylight, which will be in the latter times, when the impertinence and inconsistency of many things which now obtain in the ministry will be seen; see Eph 5:13.

Because it shall be revealed by fire: not that day, but the man's work, or doctrine:

and the fire shall try every man's work of what sort it is; by the fire is meant, not the general conflagration of the world, when that, and all that is therein, will be burnt up; much less the fire of purgatory, the "papists" dream of, for the punishment of evil actions; for the apostle is not speaking of the actions of men, good or bad, but of the doctrines of ministers; rather the fire of tribulation and affliction, which, as it is for the trial of the grace of faith, so of the doctrine of faith, whereby it becomes much more precious than of gold that perisheth; or of some fiery dispensation of God's vengeance, as on Jerusalem: though the word of God, which is as fire, seems to be intended; which in some certain times so blazes forth, and will more especially in the latter day, that by the light of it, both ministers and churches will be able to see clearly the bright shining lustre of the gold, silver, and precious stones; and with so much heat, as to burn up the wood, hay, and stubble; when the difference between these things will be most easily discerned.

Every man's work--each teacher's superstructure on the foundation.

the day--of the Lord (Co1 1:8; Heb 10:25; Th1 5:4). The article is emphatic, "The day," that is, the great day of days, the long expected day.

declare it--old English for "make it clear" (Co1 4:4).

it shall be revealed by fire--it, that is, "every man's work." Rather, "He," the Lord, whose day it is (Th2 1:7-8). Translate literally, "is being revealed (the present in the Greek implies the certainty and nearness of the event, Rev 22:10, Rev 22:20) in fire" (Mal 3:3; Mal 4:1). The fire (probably figurative here, as the gold, hay, &c.) is not purgatory (as Rome teaches, that is, purificatory and punitive), but probatory, not restricted to those dying in "venial sin"; the supposed intermediate class between those entering heaven at once, and those dying in mortal sin who go to hell, but universal, testing the godly and ungodly alike (Co2 5:10; compare Mar 9:49). This fire is not till the last day, the supposed fire of purgatory begins at death. The fire of Paul is to try the works, the fire of purgatory the persons, of men. Paul's fire causes "loss" to the sufferers; Rome's purgatory, great gain, namely, heaven at last to those purged by it, if only it were true. Thus this passage, quoted by Rome for, is altogether against, purgatory. "It was not this doctrine that gave rise to prayers for the dead; but the practice of praying for the dead [which crept in from the affectionate but mistaken solicitude of survivors] gave rise to the doctrine" [WHATELY].