During Assyria’s conquest of Israel, what side did Judah take? Relations between Israel and Judah were fluid. They were sometimes allies and sometimes adversaries. During Assyria’s long campaign against Israel culminating in the siege of Samaria and subsequent mass deportation, did Judah side with Israel, with Assyria, remain neutral, or oscillate between these positions as things got worse for Israel?
In 721 BCE, the Assyrian army captured the Israelite capital at Samaria and carried away the citizens of the northern Kingdom of Israel into captivity. The virtual destruction of Israel left the southern kingdom, Judah, to fend for itself among warring Near-Eastern kingdoms. After the fall of the northern kingdom, the kings of Judah tried to extend their influence and protection to those inhabitants who had not been exiled. They also sought to extend their authority northward into areas previously controlled by the Israeli kingdom.


According to 2 Kings 18, while Sennacherib was besieging Lachish, he received a message from Hezekiah offering to pay tribute in exchange for Assyrian withdrawal. According to the Hebrew Bible, Hezekiah paid 300 talents of silver and 30 talents of gold to Assyria—a price so heavy that he was forced to empty the temple and royal treasury of silver and strip the gold from the doorposts of Solomon's temple. Nevertheless, Sennacherib marched on Jerusalem with a large army. When the Assyrian force arrived, its field commander Rabshakeh brought a message from Sennacherib. In an attempt to demoralize the Judeans, the field commander announced to the people on the city walls that Hezekiah was deceiving them, and that Yahweh could not deliver Jerusalem from the king of Assyria. He listed the gods of other peoples defeated by Sennacherib then asked, &quot;Who of all the gods of these countries has been able to save his land from me?&quot;


During the siege, Hezekiah dressed in sackcloth (a sign of mourning), but the prophet Isaiah assured him that the city would be delivered and Sennacherib would fail.1 Overnight, an angel killed 185,000 Assyrian troops.[2]

All quoted from Wikipedia - Assyrian Siege of Jerusalem