What does Genesis 1:9 mean?

Verse 9 begins the third day of God's creation week. On this day, God continues to refine His creation by adding more detail and order to the earth. On day one, God created light and separated day from night. On day two, He created a "firmament" which we would think of as the sky. These follow the rigid structure of Genesis chapter 1: God speaks, creates, observes, declares His creation "good," and then numbers the day. Each of the first three days prepares for something God will create on a corresponding day in the second half of this creation week.

Here, in verse 9, God separates land from ocean. More specifically, He commands the waters of the earth to be gathered into "one place," and that the dry land appear. This doesn't necessarily mean that God created one single ocean, as we would understand it. However, looking at the earth as seen today, all of the "oceans" are connected into one single, massive, continuous body of water. In the next verse, these waters are called "seas." The word picture presented here is a global body of water punctuated by one or more land masses.

Once again, the emphasis is not on minute details, but a "big picture." The point of this verse, as with the rest of Genesis chapter one, is crediting God—and God alone—with the power and authority to create all we see.

As with verse 7, God's ability to create is understated, using the Hebrew phrase wa yehi kēn: "and it was so." For God, this act of creation is no more or less complex than this: He commands, and it is so. We stand in awe at the power being described here. With a sentence, God brings dry, habitable land to the earth, ready to support the abundance of life that He is about to create.