'Alliances' in the Bible

But if you ever turn away and make alliances with these nations that remain near you, and intermarry with them and establish friendly relations with them,

Eglon formed alliances with the Ammonites and Amalekites. He came and defeated Israel, and they seized the City of Date Palm Trees.

For you have forsaken your people, house of Jacob, because they are full from [the] east, and [of] soothsayers like the Philistines, and {they make alliances} with the offspring of foreigners.

"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.

“You were wearied by the length of your road,Yet you did not say, ‘It is no use.’You found renewed strength,Therefore you did not grow weak.

“This is your destiny, the portion [of judgment] measured to youFrom Me,” says the Lord,“Because you have forgotten MeAnd trusted in [pagan] lies [the counterfeit gods, and the pretense of alliance].”

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.

His intention will be to come with the strength of his entire kingdom, and he will form alliances. He will give the king of the south a daughter in marriage in order to destroy the kingdom, but it will not turn out to his advantage.

Do not be unequally bound together with unbelievers [do not make mismatched alliances with them, inconsistent with your faith]. For what partnership can righteousness have with lawlessness? Or what fellowship can light have with darkness?