| Barnes' Notes on the Bible This verse and the next are parenthetical. Here again, as in 2 Kings 17:13, the writer is led on from his account of the sins and punishment of the Israelites to glance at the similar sins and similar punishment of the Jews. It was the worst reproach which could be urged against any Jewish king, that he "walked in the way of the kings of Israel" 2 Kings 8:18; 2 Kings 16:3; 2 Chronicles 21:6; 2 Chronicles 28:2. The Baal worship is generally the special sin at which the phrase is leveled; but the meaning here seems to be wider. Compare Micah 6:16.
Gill's Exposition of the Entire BibleAlso Judah kept not the commandments of the Lord their God,.... But were infected with the idolatry of the ten tribes, and drawn into it by their example, and persisted therein, notwithstanding what befell the ten tribes; which are aggravations of the sins of them both, see Jeremiah 3:7, but walked in the statutes of Israel which they made; worshipping the calves as they did, particularly in the times of Ahaz, he setting the example, see 2 Kings 16:3.
Geneva Study BibleAlso Judah kept not the commandments of the LORD their God, but walked in the statutes of Israel which they made.
Wesley's Notes 17:19 Judah kept not - Judah's idolatry and wickedness are here remembered, as an aggravation of the sin of the Israelites, which was not only evil in itself, but mischievous to their neighbour, who by their examples were instructed in their wicked arts, and provoked to an imitation of them.
Matthew Henry's Concise Commentary17:7-23 Though the destruction of the kingdom of the ten tribes was but briefly related, it is in these verses largely commented upon, and the reasons of it given. It was destruction from the Almighty: the Assyrian was but the rod of his anger, Isa 10:5. Those that bring sin into a country or family, bring a plague into it, and will have to answer for all the mischief that follows. And vast as the outward wickedness of the world is, the secret sins, evil thoughts, desires, and purposes of mankind are much greater. There are outward sins which are marked by infamy; but ingratitude, neglect, and enmity to God, and the idolatry and impiety which proceed therefrom, are far more malignant. Without turning from every evil way, and keeping God's statutes, there can be no true godliness; but this must spring from belief of his testimony, as to wrath against all ungodliness and unrighteousness, and his mercy in Christ Jesus. | 
