John Calvin on Amos 2:3

He finally adds, And I will cut off the judge from the midst of her, and will slay her princes, saith Jehovah. God here declares, that the kingdom of the Moabites and the people shall be no more; for we know that men cannot exist as a body without some civil government. Wherever then there is an assemblage of men, there must be princes to rule and govern them. Hence, when God declares that there would be no more a judge among the Moabites, it is the same thing as if he had said, that their name would be blotted out; for had the people of Moab continued, some princes must have necessarily, as we have said, remained among them. When princes then are destroyed, the people must also perish, for there is no security for them. The Prophet then denounces not here a temporary punishment on the Moabites, but utter ruin, from which they were never to rise. This is the meaning. Let us now proceed —

Amos 2:4-5

4. Thus saith the LORD; For three transgressions of Judah, and for four, I will not turn away the punishment thereof; because they have despised the law of the Lord, and have not kept his commandments, and their lies caused them to err, after the which their fathers have walked:

4. Sic dicit Jehova, Super tribus sceleribus Jehudah, et super quatuor non convertam cum; quia spreverunt (vel, abjecerunt) legem Jehovae, et statuta ejus non custodierunt; et errare eos fecerunt mendacia sua, post quae ambulaverunt patres ipsorum:

5. But I will send a fire upon Judah, and it shall devour the palaces of Jerusalem.

5. Et mittam ignem in Jehudah, qui devorabit palatia Jerusalem.