God's promise to Abraham passed from Abraham to Isaac to Jacob/Israel, who passed it to his 12 sons/grandsons. In the last chapter of Genesis, Israel outlines what will happen to each tribe.
Later on the tribes formed a kingdom under David, whose descendants civil war'd, breaking off between north and south. The southern part was called Judaea, while the northern part was called Israel, or, by its neighbors, "Khomri/Omri", after the ruling house:
https://en.m.wikipedia.org/wiki/Omrides
The Omrides were dispersed by the Assyrians and became known as the Κιμμεροι/Kimmeroi to the Greeks. We know them as the Cimmerians:
https://en.m.wikipedia.org/wiki/Cimmerians
The Cimmerians were chased out of the Pontic Steppe by the Scythians; they journeyed into western Europe and were known to the Romans as the Cimbri and the Sicambri, among other Gaulish tribal names.
https://en.m.wikipedia.org/wiki/Cimbri
From Scandinavia, the Cimbri ventured to Wales, where they still call their land "Cymru".
https://en.m.wikipedia.org/wiki/Cymru
The Welsh were among the first nations evangelized, after Aristobulus (Romans 16:10, https://en.m.wikipedia.org/wiki/Aristobulus_of_Britannia) evangelized them.
Remember, Christ said "I am not sent but unto the lost sheep of the House of Israel."
