How the two kingdoms related to each other:
Sixty years of Hostility. Rehoboam, king of Judah, was warned through a prophet that the rending of the Kingdom was of God, and he was directed to submit. In spite of this clear injunction, Rehoboam and his successors through a period of almost sixty years, persisted in their unsuccessful efforts to subdue Israel, waging a ceaseless petty warfare.
Thirty years of alliance. In the days of Ahab of Israel and Jehoshaphat of Judah, the reigning families were bound together in a friendly alliance against foreign foes, especially the powerful kingdom of Syria.
(3) Renewed hostility
One hundred and sixty-nine years of renewed hostility. When Jehu came to the throne of Israel he destroyed the house of Ahab and severed forever the ties which bound the Two Kingdoms. From this time to the fall of Israel, in 722 B.C., there was ceaseless strife between Israel and Judah.
(4) Both loved of Jehovah
God seems to have made little difference between the Two Kingdoms, regarding them alike as his erring children. To them alike he sent prophets to warn and exhort, while in both he laid bare his arm in wonderful deliverances.