Amos refers to part of the Old Covenant: "If it is torn to pieces by an animal, then he shall bring it as evidence, and he shall not make good what was torn" (Exodus 22:13). If a lamb was stolen from the flock, the shepherd had to repay the owner for it. If a lamb was attacked and devoured by a beast, however, he had to bring proof that he had not stolen it himself. He had to show evidence that what had previously existed had been destroyed.
Whenever Israel is destroyed, the evidence of her demise will not be a leg or part of an ear, but bits of furniture like couches and beds. When others look for proof of this great nation's fate, they will find all the accouterments of opulence, luxury, self-indulgence, indolence—products of their self-concern and self-satisfaction. But they will find no effects of godly spirituality—righteousness, justice, and mercy.
The illustration of the bed and couch may be an ironic reference to Israelite sexual exploits with temple prostitutes and other ritual sexual practices (Isaiah 57:3-9). Additionally, God shows Israel committing spiritual adultery by trusting in other nations rather than God (Isaiah 31:1-3), and the destroyed bed and couch would depict His destruction of the nation for her unfaithfulness.
John W. Ritenbaugh
Prepare to Meet Your God! (The Book of Amos) (Part Two)