Because when you live for life on earth, you tend to fear people instead of God. And then you tend to do what this world tells you to do instead of what God tells you. Are you seeing the bigger picture and serving God for the sake of eternity? Or are you scrapping for your own temporary glory?
I believe He meant we can do nothing that lasts, nothing that proves to be fulfilling or worthy of our life investment. If we spend our lives on things that have no eternal value and we exist for our egos, then our efforts will prove to be worth nothing. In the end, everything temporal will burn.Only God can turn our lives into something with true meaning, which means that their impact lasts beyond the mere physical.
