What does Psalm 33:7 mean?

Genesis 1:6–7 reports: "And God said, 'Let there be an expanse in the midst of the waters, and let it separate the waters from the waters.' And God made the expanse and separated the waters that were under the expanse from the waters that were above the expanse. And it was so." Later, "God said, 'Let the waters under the heavens be gathered together into one place, and let the dry land appear.' And it was so. God called the dry land Earth, and the waters that were gathered together he called Seas. And God saw that it was good" (Genesis 1:9–10). Once again, God's creative activity is linked to His speaking a word.

In creating the seas and oceans, God fixed boundaries for them (Job 38:8–11); otherwise, they would have covered the whole earth. He also created the seabed and underground caverns to contain the waters. When God sent the Noahic flood, "all the fountains of the great deep burst forth" (Genesis 7:11). This phenomenal event occurred because God, who created the seas and oceans, was fully in charge of them, proving He is all-powerful and deserving of praise.