For the transgression of Jacob is all this, and for the sins of the house of Israel. What is the transgression of Jacob? is it not {d} Samaria? and what are the high {e} places of Judah? are they not Jerusalem?

(d) Samaria, which should have been an example to all Israel of true religion and justice, was the dirty pool and the tank that all idolatry and corruption was kept alive in, and who prided themselves in their father Jacob, and boasted of him.

(e) That is, the idolatry and infection.

Wesley's Notes

1:5 Jacob - The sons of Jacob, the ten tribes. What - Or, who is the spring, and cause of that overflowing transgression? Of Jacob - The kingdom of the ten tribes, the head of which was Samaria, where the kings had their residence, where they worshiped idols, and set an example to the rest of the Israelitish kingdom. And what - Or, who is the cause of the high places, and the idolatry there practised? Jerusalem - Which was the chief city of that kingdom, and had the same influence over Judah, as Samaria had on the ten tribes.

Jamieson-Fausset-Brown Bible Commentary

5. For the transgression of Jacob is all this-All these terrors attending Jehovah's coming are caused by the sins of Jacob or Israel, that is, the whole people.

What is the transgression of Jacob?-Taking up the question often in the mouths of the people when reproved, "What is our transgression?" (compare Mal 1:6, 7), He answers, Is it not Samaria? Is not that city (the seat of the calf-worship) the cause of Jacob's apostasy (1Ki 14:16; 15:26, 34; 16:13, 19, 25, 30)?

and what are the high places of Judah?-What city is the cause of the idolatries on the high places of Judah? Is it not Jerusalem (compare 2Ki 18:4)?

Matthew Henry's Concise Commentary

1:1-7 The earth is called upon, with all that are therein, to hear the prophet. God's holy temple will not protect false professors. Neither men of high degree, as the mountains, nor men of low degree, as the valleys, can secure themselves or the land from the judgments of God. If sin be found in God's people he will not spare them; and their sins are most provoking to him, for they are most reproaching. When we feel the smart of sin, it behoves us to seek what is the sin we smart for. Persons and places most exalted, are most exposed to spiritual diseases. The vices of leaders and rulers shall be surely and sorely punished. The punishment answers the sin. What they gave to idols, never shall prosper, nor do them any good. What is got by one lust, is wasted on another.