Jamieson, Fausset and Brown on Isaiah 66:19

19. sign--a banner on a high place, to indicate the place of meeting for the dispersed Jewish exiles, preparatory to their return to their land (Is 5:26; 11:12; 62:10).

those that escape of them--the Gentile survivors spared by God (see on Is 66:18; Zec 14:16). Is 2:2, 3; Mi 5:7; and Zec 14:16-19 represent it, not that the Jews go as missionaries to the Gentiles, but that the Gentiles come up to Jerusalem to learn the Lord's ways there.

Tarshish--Tartessus in Spain, in the west.

Pul--east and north of Africa: probably the same as Philoe, an island in the Nile, called by the Egyptians Pilak, that is, the border country, being between Egypt and Ethiopia [Bochart].

Lud--the Libyans of Africa (Ge 10:13), Ludim being son of Mizraim (Egypt): an Ethiopian people famous as bowmen (Jr 46:9): employed as mercenaries by Tyre and Egypt (Eze 27:10; 30:5).

Tubal--Tibarenians, in Asia Minor, south of the Caucasus, between the Black Sea and Araxes. Or, the Iberians [Josephus]. Italy [Jerome].

Javan--the Greeks; called Ionians, including all the descendants of Javan, both in Greece and in Asia Minor (Ge 10:2-4).

my glory ... Gentiles--(Mal 1:11).