Jamieson, Fausset and Brown on Malachi 1:4

4. Whereas--"But if" Edom say [Maurer]. Edom may strive as she may to recover herself, but it shall be in vain, for I doom her to perpetual desolation, whereas I restore Israel. This Jehovah states, to illustrate His gratuitous love to Israel, rather than to Edom.

border of wickedness--a region given over to the curse of reprobation [Calvin]. For a time Judea seemed as desolate as Idumea; but though the latter was once the highway of Eastern commerce, now the lonely rock-houses of Petra attest the fulfilment of the prophecy. It is still "the border of wickedness," being the resort of the marauding tribes of the desert. Judea's restoration, though delayed, is yet certain.

the Lord hath indignation--"the people of My curse" (Is 34:5).