it is not only he who commits sin who is separated from God and becomes His enemy, but also he who loves it and covets something, or has an attachment in his heart to anything that is on earth. This constitutes friendship with the world (James 4:4). Thus is is clearly proven that, even if one is deprived of everything and commits no sin whatever in action, but merely likes it and favors it and, so to speak, is attached to it, he is an enemy of God. Thus John says, "If any one loves the world, love for the Father is not in him" (1 John 2:15). So the Lord Himself says, "You must love the Lord your God with all your mind and with all your strength and with all your soul" (Mk. 12:30). Therefore he who craves or has an attachment to anything else transgresses this commandment.

(Saint Symeon the New Theologian)