Hear, all ye people; hearken, O earth, and all that therein is: and let the Lord GOD be witness against you, the Lord from his holy temple.
Hear, all ye people; hearken, O earth, and all that therein is - Hebrew, whatever fills it. Micaiah, son of Imlah, our prophet's namesake, begins his prophecy similarly - "Hearken, O people, every one of you." Micah designedly uses the same preface, implying that his ministrations are a continuation of his predecessor's of the same name. Both probably had before their mind Moses' similar attestation of heaven and earth in a like case (Deuteronomy 31:28; Deuteronomy 32:1: cf. Isaiah 1:2, "Hear, O heavens, and give ear, O earth").
And let the Lord God be witness against you - namely, that none of you can say, when the time of your punishment shall come, that you were not forewarned. God, whose mouthpiece I am, is witness against you, that when these, my prophecies of judgment, come to pass upon you, ye cannot say ye did not hear the word of God beforehand, so as to repent in time. The punishment denounced is stated at Micah 4:3, etc.
The Lord from his holy temple - i:e., heaven (1 Kings 8:30, "Hear thou in heaven, thy dwelling place;" Psalms 11:4, "The Lord is in his holy temple: the Lord's throne is in heaven;" Jonah 2:7; cf. Romans 1:18, "The wrath of God is revealed from heaven"). From heaven the Lord will come forth "to punish the inhabitants of the earth for their iniquity" (Isaiah 26:21).