Genesis 2:6

But there went up a mist from the earth, and watered the whole face of the ground.

​As it pertains to this verse, John MacArthur writes in his commentary:

This should be better translated "flow".  It indicates that water came up from beneath the ground as springs and spread over the whole earth as an uninterrupted cycle of water.  After the fall, rain became the primary means of watering the earth and allowed for floods and droughts that did not exist originally. Rains also allowed God to judge through rains and droughts.  

As I read this verse, it dawned on me, as it has many times, that in the sovereignty of God, He is free to do whatever He chooses whenever He chooses.  He chose to create the firmament first, with no means provided to moisten it.  Of course, He could have had a built in system to water the earth...we will never know because we were not there, and God does not give us His blueprints on every single detail of creation.  But we do know that at some point, He decided that He would allow this "mist" to come up from the ground:  what seems to be a constant stream of water that provided the hydration that the earth and the grass and the plants and the trees needed in order to survive.

By providing this mist, God also provided Himself with a great opportunity, as Dr. MacArthur so eloquently pointed out, to judge the earth through giving us too much rain or withholding the rain altogether.  We saw that in Genesis 7:17, where God flooded the earth because man was so wicked.  Genesis 7:5-7 says, "And GOD saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually.
And it repented the LORD that He had made man on the earth, and it grieved Him at his heart.
And the LORD said, I will destroy man whom I have created from the face of the earth; both man, and beast, and the creeping thing, and the fowls of the air; for it repenteth Me that I have made them."  God used the tool that He had created for the earth's hydration to judge the world because of its abominable sins.  

God is still using that tool, the rain, to judge the earth.  We read online and hear in the news all the time about some city or town that has been devastated by flooding.  Recently, there was flooding in New York that apparently came very suddenly, catching many by surprise.  I remember back in 2005 when the state of Louisiana was hit with one of the most devastating hurricanes of my lifetime.  I remember a hurricane hit my home state of North Carolina back in 1996.  The eye of that storm passed right through my neighborhood!  The rains of the outer bands did devastating damage to our city and our state.  There are many other rainstorms, tsunamis, and hurricanes that I could name, but I think you get the point.  I believe that God uses these storms and disasters to get our attention and to remind the world that He is God, and there is nothing that anyone can do to control Him.