Charles Ellicott 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)

Declare it in the isles far away ... —The “isles” appear here, as in Psalms 72:10, Isaiah 40:15, Isaiah 41:1, Isaiah 49:1, Isaiah 66:19, as the vague representative of the distant lands of the west—sometimes (Jeremiah 2:10) with the addition of Chittim. Of the isles so referred to, Cyprus and Crete, so far as any definite localities were thought of, would probably be most conspicuous. Both the “nations” and the “isles” represent the heathen whom the prophet calls to join in the praises offered by Israel.