Albert Barnes Commentary Psalms 50:1

"The Mighty One, God, Jehovah, hath spoken, And called the earth from the rising of the sun unto the going down thereof." — Psalms 50:1 (ASV)

The mighty God, even the Lord - Even “Yahweh,” for this is the original word. The Septuagint and Vulgate render this “The God of gods, the Lord.” DeWette renders it, “God, God Jehovah, speaks.” Prof. Alexander, “The Almighty, God, Jehovah, speaks;” and remarks that the word “mighty” is not an adjective agreeing with the next word (“the mighty God”), but a substantive in apposition with it. The idea is, that he who speaks is the true God, the Supreme Ruler of the universe. It is “that” God who has a right to call the world to judgment, and who has power to execute his will.

Has spoken - Or rather, “speaks.” That is, the psalmist represents him as now speaking, and as calling the world to judgment.

And called the earth - Addressed all the inhabitants of the world, all dwellers on the earth.

From the rising of the sun to the going down of it - From the place where the sun seems to rise, to the place where it seems to set; that is, all the world. Compare the notes at (Isaiah 59:19). See also (Malachi 1:11); (Psalms 113:3). The call is made to all the earth, to all the human race.

The scene is imaginary as represented by the psalmist, but it is founded on a true representation of what will occur—of the universal judgment, when all nations shall be summoned to appear before the final Judge. See (Matthew 25:32); (Revelation 20:11–14).