"In the beginning, God created the heavens and the earth....And God said, "Let there be...and there was." This pretty well summarizes Genesis chapter 1. Have you considered the impact of it?
God spoke, and things came into being. Sure, on one level, this is a blinding flash of the obvious. But when is the last time you spoke and something sprang into existence? Well of course not, you're not God, right? True, but keep reading....
"Because....you have eaten of the tree of which I commanded you, 'you shall not eat of it,'....By the sweat of your face you shall eat bread until you return to the ground." (Genesis 3:17-19)
Question: How did Adam work in the garden without sweating before the fall or the curse?
Possible answer: jump ahead to Matthew 21:19 "And seeing a fig tree by the wayside, he [Jesus] went to it and found nothing on it but only leaves. and he said to it, 'May no fruit ever come from you again!' And the fig tree withered at once." Jesus goes on to explain to the disciples that this is nothing unusual, if they have faith, they can even tell mountains to get up and jump in the ocean, and they will.
Okay, I've never told a mountain to get out of the way. You? I've certainly talked to a few traffic jams lately, but not much luck there, either.
What's the point?
In the spiritual realm (God is spirit) words have obvious power. Consider the miracles of Jesus, the manner we generally see (with some exceptions) is he speaks, and something happens. The Centurion counted on that cause and effect in Matthew 8.
God works, at least as far as we have recorded in the scriptures, through speaking. With God, his words literally mean things. He speaks, and there is some thing where before he spoke there was no thing.
What's the implication for you and I as disciples of Jesus?
We are spiritual beings, too. We inhabit the flesh. We are used to doing things through the flesh in a very literal sense. We touch things and they move. We use tools to create things. But, as hinted at in the above verses, our words are much more powerful than we (and certainly the world) gives them credit for.
God created the heavens and the earth by speaking, and he will re-create it all again by speaking. Jesus healed the blind, lame and leprous by speaking to them. He cast out demons and raised the dead by speaking.
We are given some indications that our words have heavy significance as well. Consider Jesus' words to Peter, "I will give you the keys of the kingdom of heaven, and whatever you bind on earth shall be bound in heaven, and whatever you loose on earth shall be loosed in heaven." (Matthew 16:19)
If we take that seriously, there is some serious power. If we take Jesus' earlier words about trees and mountains seriously, it is hardly trivial.
"Let the words of my mouth and the meditation of my heart be acceptable in your sight, O LORD, my rock and redeemer." (Psalm 19:14) Because, apparently, there is more to it than we realize....