What does Proverbs 25:28 mean?

In the ancient world, the primary defense of a city was its walls. Unless an army was exceptionally large or very well-prepared, cities could take shelter behind walls and wait out an attack. This did not make a walled city invincible, but it did make an enormous difference in their defensive ability. The book of Nehemiah reports the rebuilding of Jerusalem's broken walls and the attempt of the Jews' enemies to stop the effort. Without good walls, the city was vulnerable to attack. In fact, it was virtually waiting to be conquered.

Here, Solomon (Proverbs 25:1) notes that a person lacking self-discipline is also defenseless. He is vulnerable to attacks from the enemy; especially relevant here the spiritual temptations of Satan (Ephesians 6:12). Self-control is much like a wall against temptation. It does not make the temptation go away, itself. Yet it helps a person resist until the temptation passes or is chased off.

The Devil often assaults us at our weakest points, which vary among believers. Pride is a common weakness (Proverbs 25:27). Other weaknesses may be illicit sexual desire, a love of money, a lust for pleasure, a craving for fame, selfish ambition, a materialist attitude, or some other weakness. The apostle Peter summons believers to "be sober-minded; be watchful. Your adversary the devil prowls around like a roaring lion, seeking someone to devour" (1 Peter 5:8). Knowing how vulnerable to spiritual defeat he was, Paul practiced self-discipline. He writes in 1 Corinthians 9:27: "I discipline my body and keep it under control, lest after preaching to others I myself should be disqualified."