'Alliances' in the Bible

"Oh, you stubborn children," declares the LORD, "who carry out plans but they are not mine, and who make alliances but not by my Spirit, piling sin upon sin.

After a number of years, they'll become allies and the daughter of the southern king will go to the northern king in order to craft alliances. But she won't remain in power, nor will he retain his power. Instead, she'll be surrendered, along with her entourage, the one who fathered her, and the one who supported her at that time.