Proverbs 18:11
"The rich man’s wealth is his strong city, and as an high wall in his own conceit."
Cross References (ranked by relevance)
Proverbs 10:15
The rich man’s wealth is his strong city: the destruction of the poor is their poverty.
Ecclesiastes 7:12
For wisdom is a defence, and money is a defence: but the excellency of knowledge is, that wisdom giveth life to them that have it.
Deuteronomy 32:31
For their rock is not as our Rock, even our enemies themselves being judges.
Proverbs 11:4
Riches profit not in the day of wrath: but righteousness delivereth from death.