⚑ The first of four occurrences of `תּוֹרָה` in this chapter. What the word means here governs 28:7 and 28:9 as well, and this entry settles it once.
Quick answer
Abandon the teaching and you end up applauding the people it warned you about. Keep it and you find yourself in conflict with them. The verse describes two trajectories, not two legal statuses.
Read both lines
The observation is sharper than it first looks. The verse does not say those who forsake instruction become wicked; it says they praise the wicked, which is a later and stranger stage. Once the standard is gone, the man who ignores it starts looking impressive, and admiration replaces judgment. The second line is the uncomfortable half: keeping the teaching does not produce peace, it produces friction, because you are now the person who will not applaud.
Why translations differ
The word is תּוֹרָה, and English versions render it "law," which in a modern ear means Sinai. In this book it demonstrably does not have to. Proverbs calls a mother's teaching torah at 1:8 and again at 6:20, "do not forsake the law of your mother." It calls a wise man's teaching torah at 13:14, "the law of the wise is a fountain of life." And 31:26 puts "the law of kindness" on a woman's tongue. A mother's torah and a woman's torah of kindness cannot be the Mosaic covenant, so the word's ordinary range in Proverbs is instruction, teaching, direction for living.
Whether these four verses in chapter 28 mean the father's instruction the book has been giving since chapter one, or the Mosaic law specifically, or deliberately both, is genuinely debated and the catalog does not settle it. What matters for a reader is that "law" here is not automatically a reference to a legal code, and that nothing in this chapter establishes the Mosaic law as the Christian's rule of life. What governs a believer's conduct is love, which is what the law was always reaching for.
Related: Proverbs 28:7 · Proverbs 28:9 · Proverbs 1:8 · Proverbs 13:14 · Proverbs 31:26
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.