Judah. Hosea 1:7 is not an "interpolation", but is. definite and distinctive contrast with the prophecy concerning Israel.
by the LORD their God. by (Jehovah their Elohim: i.e. the Messiah, or the angel of Jehovah. See 2 Kings 19:35. But it looks forward to the future fulfillment, which will exhaust the prophecy in the destruction of Antichrist (Isaiah 11:4; 2 Thessalonians 2:8, &c).