1 John 2:15-17 (ESV)
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.  For all that is in the world— the desires of the flesh and the desires of the eyes and pride in possessions—is not from the Father but is from the world.  And the world is passing away along with its desires, but whoever does the will of God abides forever.
“Do not love the world or the things in the world.” It seems pretty self explanatory, what John is getting at here. But for the sake of clarity I am going to say he is using the world in a very specific sense here. There is a manner in which Christians are called to love the world. We are to love the world in the same way Christ loved the world, sacrificing himself for it. But here is meant the people of the world. And Christians having been loved by Christ then love the world with his love, reflecting this love in what they say and do.
But there is another love for the world which we should avoid and often fall into. That is we begin to love the things of the world, the very world that is our enemy, and does not want to see God’s name be hallowed, or his will be done. We begin to love the world as people of the world love the world. We try to serve two masters, but it is God we begin to despise. We cannot afford to love the world in this manner, lest we be destroyed with the world we love. It isn’t to say we can’t at times enjoy the things of this world. God blesses us with so much in this life, and we should enjoy those things with which he blesses us, the daily bread that he gives us. But we dare not let those things become our Gods. It isn’t smart. In the end the things of this world are going to pass away, and we may pass away long before they do. King Tut’s tomb filled with all the treasures of his love, has been gutted, and King Tut has passed away. In the end the treasures of his tomb will also pass away and there will be nothing left. Few of us can ever aspire to his fame. His fame will fade and be remembered no more with the end of the world. But whoever does the will of God abides forever. Believing in Christ, and loving the world as he loved it, we do the will of God and abide forever having eternal life.