isaiah 27:13 And it shall come to pass in that day, that the great trumpet shall be blown, and they shall come which were ready to perish in the land of Assyria, and the outcasts in the land of Egypt, and shall worship the LORD in the holy mount at Jerusalem. - Free Bible Online

      13. great trumpet--image from the trumpets blown on the first day of the seventh month to summon the people to a holy convocation (Le 23:24). Antitypically, the gospel trumpet (Re 11:15; 14:6) which the Jews shall hearken to in the last days (Zec 12:10; 13:1). As the passover in the first month answers to Christ's crucifixion, so the day of atonement and the idea of "salvation" connected with the feast of tabernacles in the same seventh month, answer to the crowning of "redemption" at His second coming; therefore redemption is put last in 1Co 1:30.
      Assyria--whither the ten tribes had been carried; Babylonia is mainly meant, to which Assyria at that time belonged; the two tribes were restored, and some of the ten accompanied them. However, "Assyria" is designedly used to point ultimately to the future restoration of the ten fully, never yet accomplished (Jer 3:18).
      Egypt--whither many had fled at the Babylonish captivity (Jer 41:17, 18). Compare as to the future restoration, Isa 11:11, 12, 16; 51:9-16 ("Rahab" being Egypt).

JFB.