Two sentence recap: The northern kingdom of Israel went into Assyrian captivity in three stages, the final one occurring with the fall of Samaria in 722 BC. The southern kingdom of Judah went into Babylonian captivity over a century later, with the fall of Jerusalem in 586 BC.
Those readers less familiar with the history of God’s earthly people may wonder why an empire as aggressively expansionist as the Assyrian would be satisfied with devouring only the northern kingdom, leaving the south to its own devices.
The answer is that it wasn’t.