1 John 2:15
 Do not love the world or the things in the world. If anyone loves the world, the love of the Father is not in him. (ESV)
We are created in the image of God. There are so many wonderful aspects about that fact that we could explore, but as it relates to this verse that we are looking at today we discover that we are created to love. In the Garden of Eden you have the first couple loving the God who created them. There was a genuine love for the father. They used to walk with him in the cool of the evening. Tragically, that love was deeply corrupted by sin.
We are still created to love. But, because of sin, our propensity is to sin and rebel against the love of God and love things other than the Father. John says that we are not to love the world or the things in the world. While he does not mean the physical universe (the earth, plants, trees, etc.) the case can be made that worshiping the created order is idolatry. In Romans 1 mankind is judged by God because they rejected the knowledge of God and worshiped the creation rather than the Creator.
The world that John is speaking of is a system rather than a creation. Satan is referred to as the god of this world. It is his value system that John warns us to stay away from. If we belong to Christ then we are to love him, and not love a value system that is comprised of pride, lust, rebellion, envy, greed, deception, and every other sinful desire that Satan places before us. We cannot love both God and the world. John commands us to choose.
Who do you love? Are you frustrated in your love relationship with God because you have been cheating on him with the world? If so, repent, and come back to the Lord. He loves you and will welcome you back.