Hearken... subdue. — The verbs should be taken in a future sense, “Oh that my people would hearken ... I should soon subdue,” &c. The poet changes from reminiscences of the past to the needs of the present.
Related Commentaries of Psalms 81:13
Psalms 81:13-14
13 Oh that my people had hearkened unto me, and Israel had walked in my ways!
14 I should soon have subdued their enemies, and turned my hand against their adversaries.