What prophecies was Paul referring to when he said “do not despise prophecies” in 1 Thessalonians 5:20?
1 Thessalonians 5:19-22 (ESV):
19 Do not quench the Spirit. 20 Do not despise prophecies, 21 but test
everything; hold fast what is good. 22 Abstain from every form of
evil.
Paul's letter was addressed to the Christian congregation of Thessalonica, so he is referring to in verse 20, to all prophecies found in the canon of Scripture.
A dedicated Christian that claims to serve the true God then goes out along with the world and its corrupt influences and partakes in its corruption adds to his sins, because he is treating prophecies with contempt.
He is ignoring all the words that God has caused to be spoken through the mouths of His prophets and spokesmen. Such a professed Christian has these words from the God he claims to serve; he has the Bible but ignores it in favor of men’s ideas, which appeal to his selfish desires. To do this is to insult God, to be a hypocrite and more reprehensible than the unbelievers.
How are we to test them (v21)? To examine and scrutinize something to see if it is genuine, by checking the Greek Septuagint version of the Hebrew scriptures and any other NT Greek scriptures available at the time.