Genesis 3:19 "...You are dust, and when you die, you will return to the dust."
Do you remember what it was like being a part of the dust? Do you remember if it was a really good time? Do you remember anything about it? Of course not! Then why do we focus so much on the earthly things when we are guaranteed we cannot take anything of that sort with us?
Many ideas come to my mind when I think about "earthly things", such as sports. We train and train for big games and it eventually takes over our entire being if we aren't careful. Then you finally win that huge trophy and for the rest of your life you don't let anyone forget. It's at the center of your world. Then somehow, the Lord decides your time is up on the earth. And like he promised, you returned to the dust. Whether your body has become one with the ground or your spirit is doing its thing in heaven, I guarantee that you won't be thinking, "Man, I wish I would have spent just a little more time with that trophy." Or, "I really hope everyone remembers that I was a part of the huge win." And if you do find yourself thinking that, then you're more than likely not dead yet.
It just baffles me that we know what is ultimately more important, but we still train with the earth as if we were on it's team. I'll let you in on a little secret that might shock some of you...the world WILL end. It's just as much a promise and guarantee as it is accepting Jesus will get you to heaven. Stop living with a first person mind set, meaning "What do I want; How will that affect me; What will I get out of it." Instead, live with a second person mind set: "Lord, what do you want; How can I glorify your name in this situation."
So train your spirit. It is the only thing you can take in the end. And the end is forever. So train it well.
1 John 2:17 "The world and everything that people want in it are passing away, but the person who does what God wants lives forever."