Jamieson, Fausset and Brown on 1 John 2:15

15. Love not the world--that lieth in the wicked one (1Jo 5:19), whom ye young men have overcome. Having once for all, through faith, overcome the world (1Jo 4:4; 5:4), carry forward the conquest by not loving it. "The world" here means "man, and man's world" [Alford], in his and its state as fallen from God. "God loved [with the love of compassion] the world," and we should feel the same kind of love for the fallen world; but we are not to love the world with congeniality and sympathy in its alienation from God; we cannot have this latter kind of love for the God-estranged world, and yet have also "the love of the Father in" us.

neither--Greek, "nor yet." A man might deny in general that he loved the world, while keenly following some one of THE THINGS IN IT: its riches, honors, or pleasures; this clause prevents him escaping from conviction.

any man--therefore the warning, though primarily addressed to the young, applies to all.

love of--that is, towards "the Father." The two, God and the (sinful) world, are so opposed, that both cannot be congenially loved at once.