Why shouldn't Christians get taken up with the world?
Christians should not be taken up with the world because loving the world and its things means the love of the Father is not in them. The world’s desires—flesh, eyes, and pride of life—are not of the Father, and this whole world system will pass away, while those who do God’s will abide forever.
Les explains from 1 John 2:15–17 that believers should not love the world or the things in the world, because if anyone loves the world, the love of the Father is not in him. He says this means our priorities are upside down. Everything in the world—the desires of the flesh, the desires of the eyes, and the pride of life—is not of the Father but is of the world. Les teaches that the reason not to be taken up with it is that the whole world system is going to pass away, and when it leaves, the desires for it will pass as well. But the one who does the will of God abides forever. He applies this by asking young people why they would gamble their eternity for 15 or 20 years of the fast lane, saying it is not worth it.
And the world passeth away, and the lust thereof: but he that doeth the will of God abideth for ever.