Isaiah 27:13
וְהָיָה בַּיּוֹם הַהוּא יִתָּקַע בְּשׁוֹפָר גָּדוֹל וּבָאוּ הָאֹבְדִים בְּאֶרֶץ אַשּׁוּר וְהַנִּדָּחִים בְּאֶרֶץ מִצְרָיִם וְהִשְׁתַּחֲווּ ה’ בְּהַר הַקֹּדֶשׁ בִּירוּשָׁלִָם
It shall come to pass on that day that a great horn shall be blown, and they will come who were lost in the land of Assyria and who were dispersed in the land of Egypt, and they will worship Hashem at the holy mountain in Jerusalem.
The tenth bracha of Shemoneh Esrei, Kibbutz Galuyos (the ingathering of exiles), references this verse from Isaiah. The Radak explains the “great shofar” as a metaphor: the Jews will gather as if a great shofar sounded throughout the world, calling them back home.