What does Genesis 2:10 mean?
The next five verses are a parenthesis: a separate section of the text. From a narrative standpoint, this passage could be set off to the side without disrupting the flow of the story. These words explain the geography of the Garden of Eden, and give more information on where it was located. The main story will resume in verse 15.According to verse 10, a mighty river watered Eden's garden. As mentioned before, "Eden" includes more than just the garden; it seems to be a geographical region. After leaving the area of Eden itself, this river split into four separate streams. These are listed in verses 11 through 14 as the Pishon, Gihon, Tigris, and Euphrates. The description of those four rivers will help to locate the region of Eden—though not the specific location of the garden—in the known world of the time.
The Tigiris and Euphrates rivers are known today, in the geographical area most likely to have been near Eden. The other two rivers, however, may or may not exist today. Given that this is pre-flood geography, there is no way to say for sure if these rivers are exactly the same as the waterways currently called by those names.