Complete Commentary on the Whole Bible, by Matthew Henry, at sacred-texts.com
(Nah 3:1-7) The sins and judgments of Nineveh.
(Nah 3:8-19) Its utter destruction.
When proud sinners are brought down, others should learn not to lift themselves up. The fall of this great city should be a lesson to private persons, who increase wealth by fraud and oppression. They are preparing enemies for themselves; and if the Lord sees good to punish them in this world, they will have none to pity them. Every man who seeks his own prosperity, safety, and peace, should not only act in an upright, honourable manner, but with kindness to all.
Strong-holds, even the strongest, are no defence against the judgments of God. They shall be unable to do any thing for themselves. The Chaldeans and Medes would devour the land like canker-worms. The Assyrians also would be eaten up by their own numerous hired troops, which seem to be meant by the word rendered "merchants." Those that have done evil to their neighbours, will find it come home to them. Nineveh, and many other cities, states, and empires, have been ruined, and should be a warning to us. Are we better, except as there are some true Christians amongst us, who are a greater security, and a stronger defence, than all the advantages of situation or strength? When the Lord shows himself against a people, every thing they trust in must fail, or prove a disadvantage; but he continues good to Israel. He is a strong-hold for every believer in time of trouble, that cannot be stormed or taken; and he knoweth those that trust in Him.