When the Bible speaks of the world
, and it does so frequently, it is speaking of a mentality, a culture, a system that is under the control of Satan. The Bible describes him as the god of this world who has blinded the minds of those who don't believe (see 2 Corinthians 4:4).
The best definition of the world
that we find in the Bible is in 1 John 2:15–16: "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 lust of the flesh, the lust of the eyes, and the pride of life—is not of the Father but is of the world."
Every temptation that you and I will face falls under one of those three categories: the lust of the flesh, the lust of the eyes, and the pride of life.
This was true when Satan tested Jesus in the wilderness. The first temptation was to take stones and turn them into bread. That was the lust of the flesh. Then Satan basically said, "Why don't You jump off this pinnacle of the temple, and the angels will catch you?" That was the pride of life: Go ahead and do this great thing, and everyone will see how wonderful You are.
Lastly, Satan said that he would give Jesus all the kingdoms of the world in exchange for His worship. That is the lust of the eyes.
Sometimes we become frenemies with the world. Frenemies are people who are at odds with each other but then become friends—but it is not a genuine friendship at all. And when you are a friend of the world, then in effect you have a frenemy.