2:1 How. Cf. 1:1 and note.

He has cast down . . . the splendor. Israel’s fall into disfavor is compared to a falling star (Is. 14:12).

has not remembered. Judah is astonished that the promise to David is now apparently void (cf. Ps. 89, especially vv. 38–51). Isaiah had assured the people that God would protect Zion (e.g., Is. 37:35), and the people of Judah had absolutized these promises. They forgot their obligation to keep the terms of God’s covenant with them (Ex. 24:1–3).

his footstool. Used normally for the ark of the covenant (1 Chr. 28:2; Ps. 132:7), or the earth (Is. 66:1), it is here applied to Zion (cf. Ps. 99:5).