The Lord is a strong tower.
v.9 Destroyer. This proverb equates the one who is slack in his work to one who destroys. Lazy people are destructive to themselves and society as a whole. Laziness also causes poverty and hunger (See 10:4).
v.10 Safety. For the righteous man, the (name of the) Lord is a strong tower who he runs to and is safe. See Ps 18:2. The Lord is fully able to protect those who trust in him. The strong tower is like a storehouse that due to height and strength was impregnable.
v.11 The rich man. In contrast to v.10, here the rich man trusts in his money as his strong tower, but it is only a strong tower in his imagination. See also Ps 49.
v.12 Humility. Before his downfall a man’s heart is proud, but humility comes before honor. See 11:2 or 29:23 for similar thoughts.

Read Proverbs 18:9-12