It warns that loving the world is incompatible with the love of the Father. It lists "the desires of the flesh," "the desires of the eyes," and "pride of life" and says the world is passing away. See 1 John 2:15–17.
In 1 John 2:15–17 the writer warns readers not to set their love on “the world” or on what the world offers. He frames this as an either-or loyalty: love for the world and love connected with “the Father” do not coexist in the same person. This warning sits inside a larger section where the writer urges a way of life consistent with knowing God and staying with the community’s original message.
The passage draws a sharp contrast between two centers of loyalty: love for “the world” and love connected with “the Father” (1 John 2:15–17).
A careful answer keeps the immediate passage, the book's argument, and the whole-Bible storyline together, so the question is answered in context instead of as a detached idea.
Start with 1 John 2:15-17, then read the surrounding section so the answer stays connected to the passage's flow.
15Don`t love the world, neither the things that are in the world. If anyone loves the world, the Father`s love isn`t in him.
16For all that is in the world, the lust of the flesh, the lust of the eyes, and the pride of life, isn`t the Father`s, but is the world`s.
17The world is passing away with its lusts, but he who does God`s will remains forever.