(Pro 18:11 KJV) The rich man's wealth is his strong city, and as an high wall in his own conceit.
There are a lot of people who look at things through human eyes and make the decision about what is “strong” (5797) and what is weak. The purpose of the choice is to decide where to invest their time and how to set their priorities. You work to your strengths to compensate for your weaknesses. The ancient world was full of great cities that thought their walls would defend them. As far as I know, they all fell. One thought I hear repeated is that cities do not usually fall to attacks on their walls but are betrayed from within.
While the world is working to build walls higher and repair cracks, the real danger is in their hearts. While the ramparts are worked on, the world does not make sure that they have enough food and water to maintain a siege. It doesn’t matter how high your walls are if you pantry is empty.
So? Let the world build its walls. We need to strengthen our inner man, to develop our trust in the Lord and our obedience to His word.