And before him shall be gathered all nations: and he shall separate them one from another, as a shepherd divideth his sheep from the goats: All nations - Literally, all the nations - all the Gentile world; the Jews are necessarily included, but they were spoken of in a particular manner in the preceding chapter.
He shall separate them - Set each kind apart by themselves.
As a shepherd divideth, etc. - It does not appear that sheep and goats were ever penned or housed together, though they might feed in the same pasture; yet even this was not done but in separate flocks; so Virgil, Eclog. vii. v. 2.
Compulerantque greges Corydon et Thyrsis in unum;
Thyrsis Oves, Corydon distentas lacte
Capellas
"Thyrsis and Corydon drove their flocks together:
Thyrsin his sheep; and Corydon his goats, their udders distended with milk."
These two shepherds had distinct flocks, which fed in the same pasture, but separately; and they are only now driven together, for the convenience of the two shepherds, during the time of their musical contest.