Jamieson, Fausset and Brown on Amos 3:12

12. shepherd--a pastoral image, appropriately used by Amos, a shepherd himself.

piece of ... ear--brought by the shepherd to the owner of the sheep, so as not to have to pay for the loss (Ge 31:39; Ex 22:13). So if aught of Israel escapes, it shall be a miracle of God's goodness. It shall be but a scanty remnant. There is a kind of goat in the East the ears of which are a foot long, and proportionally broad. Perhaps the reference is to this. Compare on the image 1Sa 17:34, 35; 2Ti 4:17.

that dwell in Samaria in the corner of a bed--that is, that live luxuriously in Samaria (compare Am 6:1, 4). "A bed" means here the Oriental divan, a raised part of the room covered with cushions.

in Damascus in a couch--Jeroboam II had lately restored Damascus to Israel (2Ki 14:25, 28). So the Israelites are represented as not merely in "the corner of a bed," as in Samaria, but "in a (whole) couch," at Damascus, living in luxurious ease. Of these, now so luxurious, soon but a remnant shall be left by the foe. The destruction of Damascus and that of Samaria shall be conjoined; as here their luxurious lives, and subsequently under Pekah and Rezin their inroads on Judah, were combined (Is 7:1-8; 8:4, 9; 17:3). The parallelism of "Samaria" to "Damascus," and the Septuagint favor English Version rather than Gesenius: "on a damask couch." The Hebrew pointing, though generally expressing damask, may express the city "Damascus"; and many manuscripts point it so. Compare for Israel's overthrow, 2Ki 17:5, 6; 18:9-12.