Quick answer
Lead a good man into harm and the trap closes on you. The third line adds what happens to the one who was targeted.
Read both lines
Three lines, and the structure matters. The first names an active corruption, causing someone else to stray, which the book treats as a category worse than straying yourself. The second delivers the pit image the collection has used twice already, at 26:27 and 28:18's neighbourhood, and the pronoun is emphatic: he himself.
The third line is the addition. Without it the verse would be a warning to the corrupter; with it, it is also reassurance to the person he was aiming at. The blameless inherit good, which is a claim about outcome the book will not put a schedule on. Read as a rule it would be false, since good people are led astray and harmed. Read as the shape of things it explains why the corrupter's project is not as clever as it looks.
Related: Proverbs 26:27 · Proverbs 28:18 · Proverbs 1:18–19 · Matthew 18:6
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.