They shall walk after the Lord: he shall roar like a lien: when he shall roar, then the children shall tremble from the west. Others translate, "After the Lord shall they go as after a lion that roareth."
But this necessitates a double ellipsis of "after which." They would go after the Lord in obedience to his summons. That summons is represented as far-reaching and terrible. Calling his people to return, the Lord roars as a lion, to denote at once the loudness of the call, and the awful majesty of the Lord when thus calling his people to return.
"As a lion," says Kimchi, "which roars that the animals whose king he is may assemble to him, so the Israelites shall assemble on hearing the voice of the Lord when he roars." The roaring of the lion may signify his terrible judgments on Israel's enemies, when he calls his people home from the lands of their dispersion.
The result would be a speedy return of his children from the lands of the West—the countries round or beyond the Mediterranean.