Genesis 1:9 - Setting Boundaries

And God said, Let the waters under the heaven be gathered together unto one place, and let the dry land appear: and it was so.

God assigned a boundary upon the face of the waters, low enough to let dry land appear. The oceans were locked into vast reservoirs so the waters would not overstep God's command. The sand along the seashore mark the boundary line that the sea cannot cross, an everlasting barrier (Job 26:10; Psalm 33:7; Proverbs 8:29; Jeremiah 5:22). During the flood, God broke the reservoirs open  (Genesis 7:11); but made an everlasting covenant to never do this again Genesis 9:11).

Genesis 1:6 - When The Skies Were Created

And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.

Through the power of God's word and wisdom, the skies were spread out to divide the waters from the waters. (Job 37:18; Psalm 33:6; 136:5; Jeremiah 10:12).