Deliberately paired in placement with 18:10: two refuges, side by side.
Quick answer
Money feels like a fortress, and the proverb lets the feeling stand for one line before puncturing it: the wall is high "in his own esteem." A real shelter against many things, an imagined one against the things that matter most.
Read both lines
The first line grants what honesty must: wealth genuinely shields, buying medicine, margins, second chances, and the book has said so without sneering (10:15). The second line adds four words that relocate the structure: "in his own esteem." The wall's height is a measurement taken by the man inside it, and against the invasions that finally matter it is scenery. The placement does the preaching: one verse earlier, the righteous ran into a tower that holds. Two men, two refuges, one of which is load-bearing. Jesus told the long version about bigger barns the night a soul was required (Luke 12:16–21).
Related: Proverbs 10:15 · Proverbs 11:28 · Luke 12:16–21
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.