(21) Prove all things.--The right reading inserts a "but":--"I bid you pay all reverence to the cheering utterances of your prophets (comp. Acts 15:32); but take care! put everything to the test." That the warning was needed, or would be needed soon, is shown by 2Thessalonians 2:2. It is couched in general terms (all things), but, of course, has special reference to all things purporting to be manifestations of the Spirit. And how were these revelations to be tested? If they were not in accordance (1) with the original tradition (2Thessalonians 2:2), (2) with the supernatural inspirations of the other prophets who sat as judges (1Corinthians 14:29), (3) with enlightened common sense (1John 4:1), they could not be "good." The word "good" here is not vague and general good in the moral sense--not the same Greek word as in 1Thessalonians 5:15--but "good" in the sense of "genuine," "answering to the proper conception of what it purports to be." The same word is used in the same sense in John 10:11.

Verse 21. - Prove all things. This exhortation is closely connected with the preceding. "Prove all things," namely, whatever was advanced by the prophets in their inspired discourses (comp. 1 John 4:1, "Believe not every spirit, but try the spirits whether they are of God"). "Prove" here means to test, as metals are tested in the fire; and hence the word frequently denotes the favorable result of the testing, or approval. There was a special gift of discerning spirits in the primitive Church (1 Corinthians 12:10; 1 Corinthians 14:29). But although the words primarily refer to the testing of prophetic utterances, yet they have a general application. We should not rest our faith on the authority of others. The right of private judgment is the characteristic and privilege of Protestantism. We ought thoroughly to examine all doctrines by the test of Scripture, and then, discerning their reasons, we shall be able to take a firmer hold of them. At the same time, the fundamental principle of rationalism, that reason as such is the judge of the doctrines of revelation, is not contained in these words, and cannot be inferred from them. Hold fast; retain. That which is good; the good, the beautiful, the honorable; a different word from that rendered "good" in ver. 15. We are to retain whatever is good in those "all things" which we are to prove or test, namely, in the prophesyings.

5:16-22 We are to rejoice in creature-comforts, as if we rejoiced not, and must not expect to live many years, and rejoice in them all; but if we do rejoice in God, we may do that evermore. A truly religious life is a life of constant joy. And we should rejoice more, if we prayed more. Prayer will help forward all lawful business, and every good work. If we pray without ceasing, we shall not want matter for thanksgiving in every thing. We shall see cause to give thanks for sparing and preventing, for common and uncommon, past and present, temporal and spiritual mercies. Not only for prosperous and pleasing, but also for afflicting providences, for chastisements and corrections; for God designs all for our good, though we at present see not how they tend to it. Quench not the Spirit. Christians are said to be baptized with the Holy Ghost and with fire. He worketh as fire, by enlightening, enlivening, and purifying the souls of men. As fire is put out by taking away fuel, and as it is quenched by pouring water, or putting a great deal of earth upon it; so we must be careful not to quench the Holy Spirit, by indulging carnal lusts and affections, minding only earthly things. Believers often hinder their growth in grace, by not giving themselves up to the spiritual affections raised in their hearts by the Holy Spirit. By prophesyings, here understand the preaching of the word, the interpreting and applying the Scriptures. We must not despise preaching, though it is plain, and we are told no more than what we knew before. We must search the Scriptures. And proving all things must be to hold fast that which is good. We should abstain from sin, and whatever looks like sin, leads to it, and borders upon it. He who is not shy of the appearances of sin, who shuns not the occasions of it, and who avoids not the temptations and approaches to it, will not long keep from doing sin.Prove all things,.... That are said by the prophets, all the doctrines which they deliver; hear them, though they have not the gift of tongues, and all desirable advantages; do not reject them on that account, and refuse to hear them, for so, many useful men may be laid aside, and the Spirit of God in them be quenched; try their gifts, and attend to their doctrines, yet do not implicitly believe everything they say, but examine them according to the word of God the test and standard of truth; search the Scriptures, whether the things they say are true or not. Not openly erroneous persons, and known heretics, are to be heard and attended on, but the ministers of the word, or such who are said to have a gift of prophesying; these should make use of it, and the church should try and judge their gift, and accordingly encourage or discourage; and also their doctrines, and if false reject them, and if true receive them.

Hold fast that which is good; honest, pleasant, profitable, and agreeable to sound doctrine, to the analogy of faith, and the Scriptures of truth, and is useful and edifying, instructive both as to principle and practice; such should be held fast, that no man take it away; and be retained, though a majority may be against it, for the multitude is not always on the side of truth; and though it may be rejected by men of learning and wealth, as Christ and his doctrines were rejected by the Scribes and Pharisees, and rulers of the people; and though it may be reproached as a novel, upstart notion, or a licentious one, since these were charges against the doctrine of Christ, and his apostles; and though it may be attended with affliction and persecution, yet none of these things should move from it, or cause to let it go.