"The things that we love tells us what we are." St Thomas Aquinas 

Have you ever thought of this? How true it is. If we love material things, we are a material person with limited focus. If we love spiritual realities, then we are a spiritual person with unlimited focus. That is why Jesus urges us to focus on the things that will matter eternally. We are to use material things not as ends, but as means to do what God desires us to do. Material entities will come to end. Spiitual realities opens us up eternal realities.