2 Kings 18:11
And the king of Assyria did carry away Israel unto Assyria, and put them in Halah and in Habor by the river of Gozan, and in the cities of the Medes: And the king of Assyria did carry away Israel unto Assyria, and put them in Halah and in Habor by the river of Gozan, and in the cities of the Medes:
The king of Assyria carried Israel away from its own land into Assyria and settled the captives in Halah and in Habor by the river of Gozan and in the cities of the Medes. That deportation followed the capture and fall of Samaria, which fell only after a three-year siege. Those carried away were the people of the northern kingdom, the shattered remnant of the ten tribes, scattered among other nations and among the provinces of the Assyrian realm.
Many Israelites had already been carried away by the time Hezekiah became king of Judah. Samaria itself was captured a few years later, during Hezekiah's reign, so the deportation belongs to the earlier part of his reign. Israel's captivity came because the people disobeyed God and broke His covenant, with the Assyrians serving as the instruments God used to bring judgment.
Assyria's success in defeating Israel led the surrounding peoples and nations to question the power of Israel's God. The removal of the northern kingdom left Judah and Jerusalem exposed and brought them close to the Assyrian threat.