Deuteronomy 20:15
Thus shalt thou do unto all the cities which are very far off from thee, which are not of the cities of these nations.
Cross-references
Joshua 9:9
Parallel
In Joshua 9:9, the Gibeonites claim to come from a far country, exactly matching the condition in Deuteronomy 20:15 for offering peace.
Joshua 9:24
Historical context
Joshua 9:24 reveals the Gibeonites feared because they knew the destruction command for nearby nations, so they used the 'far city' loophole.