Robert J. Clifford, Fair Spoken and Persuading: An Interpretation of Second Isaiah (Ramsey, NJ: Paulist Press, 1984), 26:
Second Isaiah adopts the pre-exilic prophetic scenario and its presuppositions, except that he turns it around. For him, the judgment of Yahweh was not future; it had already occurred in the destruction of the Temple and the deportation of the people. Israel had suffered the consequences of its action, had “borne its sins.” A new divine decree had been issued: “‘Comfort, comfort my people,’ says your God” (40:1). The instrument of consolation was a human king, as was the instrument of punishment in pre-exilic times. Cyrus in Second Isaiah functions like the Assyrian king in First Isaiah and the Babylonian king in Jeremiah. The foreign king, Cyrus, rebuilds the Temple and brings back the people. He is a mirror image of the earlier avenging king.
The Amateur Exegete 