There is a saying that I think most of us have heard at some point in time, and it goes like this "too heavenly minded to be any earthly good". This particular saying will no doubt place an image of someone that we may know or have met that could fit this description; but if we really consider what this saying says - rather than what it implies, it is absolutely wrong. I won't go into the details of what it implies that can be extracted into something that is worth thinking about, because I think it would be more beneficial to look into the statement itself.
When Jesus gave us an example of how to pray, one of the things He said was:
Thy kingdom come. Thy will be done in earth, as it is in heaven.
To truly be heavenly minded would be having this request made with your every breath, thought, action, purpose - It is to live in the world but not of the world, consumed with kingdom work (bringing the Gospel to this lost and dying world). Really, the problem within modern Christianity is that we are not heavenly minded enough - and for this we seem to be of no earthly value. If we desire to impact this world for Christ, the only way is to be in His will, with His message. This is the only way we can be any earthly good.
But seek ye first the kingdom of God, and his righteousness...