Albert Barnes Commentary 1 Thessalonians 5:21

"prove all things; hold fast that which is good;" — 1 Thessalonians 5:21 (ASV)

Prove all things. Subject everything submitted for your belief to the proper test. The word used here (dokimazete), is one that is properly applicable to metals, referring to the art of the assayer by which the true nature and value of the metal is tested. (See Barnes' commentary on 1 Corinthians 3:13).

This trial was usually made by fire. The meaning here is that they were to examine carefully everything presented for their belief. They were not to receive it on trust, to accept it merely on assertion, or to believe it because it was urged with vehemence, zeal, or plausibility. In the various opinions and doctrines presented to them for adoption, they were to apply the appropriate tests from reason and the word of God; and they were to embrace what they found to be true, and reject what was false.

Christianity does not require people to disregard their reason or to be credulous. It does not expect them to believe anything because others say it is so. It does not make it a duty to receive as undoubted truth all that synods and councils have decreed, or all that is advanced by the ministers of religion. It is, more than any other form of religion, the friend of free inquiry, and would lead people everywhere to understand the reason for the opinions they hold. (1 Peter 3:15).

Hold fast that which is good. This refers to what is in accordance with reason and the word of God, what is suited to promote the salvation of the soul and the welfare of society. This is just as much a duty as it is to "prove all things." A person who has applied the proper tests and has discovered what is true is bound to embrace it and to hold it fast.

They are not free to throw it away, as if it were worthless, or to treat truth and falsehood alike. It is a duty they owe to themselves and to God, to adhere to it firmly, and to suffer the loss of all things rather than to abandon it.

There are few more important rules in the New Testament than the one in this passage. It shows what is the true nature of Christianity, and it is a rule whose practical value cannot help but be felt constantly in our lives. Other religions require their followers to receive everything upon trust; Christianity asks us to examine everything.

Error, superstition, bigotry, and fanaticism attempt to repress free discussion, by saying that there are certain things which are too sacred in their nature, or which have been too long held, or which are sanctioned by too many great and holy names, to permit them to be subjected to the scrutiny of common eyes or to be handled by common hands.

In opposition to all this, Christianity requires us to examine everything—no matter by whom it is held, by what councils it was ordained, by what venerable antiquity it is supported, or by what sacredness it may be invested. We are to receive no opinion until we are convinced that it is true; we are to be subjected to no pains or penalties for not believing what we do not perceive as true; and we are to be permitted to examine any opinion which our fellow human beings regard as true and which they seek to make others believe.

No popular current in favor of any doctrine, no influence which name, rank, and learning can give it, should commend it to us as certainly worthy of our belief. By whomever it is held, we are to examine it freely before we embrace it; but when we are convinced that it is true, it must be held, no matter what current or popular opinion or prejudice may be against it, no matter what ridicule may be poured upon it, and no matter even if believing it requires us to die a martyr's death.