Albert Barnes Commentary Jeremiah 31:10

"Hear the word of Jehovah, O ye nations, and declare it in the isles afar off; and say, He that scattered Israel will gather him, and keep him, as shepherd doth his flock." — Jeremiah 31:10 (ASV)

The isles - The coast land of the Mediterranean, used here to show that the most distant countries are to hear and marvel at Israel’s wonderful restoration.