I've been preparing to preach a sermon - For King and Kingdom! - from Luke 12:31-34 this past week. It will be delivered, God willing, this Sunday.
I came across this from Matthew Henry in my study:
Now by this it appears that we have laid up our treasure in heaven if our hearts be there while we are here (Luke 12:34), if we think much of heaven and keep our eye upon it, if we quicken ourselves with the hopes of it and keep ourselves in awe with the fear of falling short of it. But, if your hearts be set upon the earth and the things of it, it is to be feared that you have your treasure and portion in it, and are undone when you leave it.