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. "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 1 Thessalonians 5:15 . We are to retain whatever is good in those "all things" which we are to prove or test, namely, in the prophesyings.
Now follows a series of short admonitions. The Thessalonians were to love and honor their ministers, to live in peace among themselves, to admonish the disorderly, to encourage the faint-hearted, to support the weak, and to exercise forbearance toward all men. They were to be on their guard against revenge, to preserve Christian joyfulness, to be constant in prayer, and to maintain a thankful disposition. They were not to quench the Spirit, nor despise prophesyings, but were to test all things, retaining the good and rejecting the evil. And it was his earnest prayer for them that God would so completely sanctify them that they might be blameless at the advent of the Lord Jesus. After requesting an interest in their prayers, and solemnly charging them to read this Epistle to the assembled Church, the apostle concludes with his apostolic benediction.