Taking this verse out of context makes it seems negative, but it has a very positive message. The message is this: the world offers many seemingly good things, such as wealth, gratification of all kinds of desires, and beauty, but not everyone can grab hold of these things and no one can grab hold of them forever. We all eventually leave the world in death, and even those who work hardest to gain the most wealth, beauty, or objects of their desire don’t seem to be satisfied. In this context, John says, “Don’t love this world.” Not because we shouldn’t love the people in the world, not because we shouldn’t make use of the things the world offers, but because John desparately wants us to know that there is more to life than this. In contrast to the world, God offers us eternal things: an eternal relationship, happiness that doesn’t go away when the shininess of a new things fades, forgiveness for sins instead of punishment for making a bad investment. Those who believe in Jesus have overcome everything in him; John just wants us to take advantage of this true wealth that we have from Christ.