What does Psalm 29:4 mean?

David describes the voice of the Lord as powerful and full of majesty. This expression points out that God is king with the power to command all His subjects—every person and all nature.

How powerful is God's voice? At creation, the Lord said, "'Let there be light,' and there was light" (Genesis 1:3). He spoke, and waters separated from waters (Genesis 1:6). He spoke dry land into existence (Genesis 1:9). His spoken word created vegetation, seed-bearing plants, and fruit trees (Genesis 1:11). By His word He created the sun, moon, and stars (Genesis 1:14). Marine life, birds, and animals of all sorts owe their existence to God's spoken word (Genesis 1:20–25). Finally, God spoke man into existence as He formed Him from dust (Genesis 1:26–27).

During His earthly ministry Jesus healed many by just saying a word (John 5:8–9). He even commanded the dead to rise, and they arose (John 11:43–44). Someday, the dead will hear His voice, "and those who hear will live" (John 5:25).