Albert Barnes Commentary Psalms 76:8

"Thou didst cause sentence to be heard from heaven; The earth feared, and was still," — Psalms 76:8 (ASV)

You did cause judgment to be heard from heavens—It seemed to come from heaven; it was manifestly from you. The overthrow of these enemies of your people was a manifest judgment from you, and should be so regarded.

The earth feared—The world itself seemed to hear the voice of God, and to stand in awe.

And was still—It seemed to be profoundly attentive to what God said, and as if it reverently listened to his voice. It is not uncommon in the Scriptures to represent the earth—the hills, the mountains, the streams, the rivers, the plains—as conscious of the presence of God; as either rejoicing or trembling at his voice. Compare Psalms 65:12-13; Psalms 114:3–7; Habakkuk 3:8–11.