Isaiah 37:9

Tirhakah. — The third of the twenty-fifth, or Ethiopian dynasty of kings, So, or Sabaco, with whom Hoshea, the last king of Israel, allied himself, being the first (2 Kings 17:4). He is described in Assurbanipal’s inscriptions (Records of the Past, i. 60) as king of Mizr and Cush — i.e., Egypt and Ethiopia. The policy of Hezekiah’s counsellors had led them to court his alliance, as in Isaiah 30:31. Now, however, the Egyptian army was at least mobilised. “Rahab” was no longer “sitting still” (Isaiah 30:7).

When he heard it. — The message is in substance a repetition of its predecessors, more defiant, perhaps, as if in answer to the threatened attack of Tirhakah’s armies, which Sennacherib could scarcely fail to connect with Hezekiah’s confident hope of deliverance.