Those who prosper in their pursuit of temporal things are to be admonished that when everything accords with their wishes, they should not neglect to seek out the Giver and not fix their hearts solely on what is given. They must not love their pilgrimage instead of their [destination], nor turn the supplies they receive for their journey into hindrances to their safe arrival, nor become so exhilarated by the moon shining in the night as to shrink from beholding the bright radiance of the sun.
From Chapter 26 of the Book of Pastoral Rule,
trans. By Henry Davis, S.J.
This passage from St. Gregory’s advice to pastors is, in a sense, both a logical reflection on Jesus' words "where your treasure is, there your heart will be also," and an expansion on the famous teaching of St. Paul’s that “the love of money is the root of all evil.” It is not the things themselves that corrupt, but the love of the things apart from God—and the illusion of power and control they give—that corrupts us. When we become convinced that our whims, preferences, and tastes are the objective measure of value and Truth, we cease to be open to God's word and will; we have in effect come to prefer the journey to the destination... about which we can delude ourselves until we actually arrive!
As participants in a consumerist society, we need to be kept aware that the love of unthinking consumption is in itself a deeply sinful and corrupting practice.