Romans 12:2 And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.
The phrase “this world” is a reference to the present evil world system which is:
Under the authority of “the god of this world” – 2 Corinthians 4:4
Under the influence of the philosophy of Satan – Colossians 2:8
Carried along by a value system that appeals to “the lust of the flesh, the lust of the eyes, and the pride of life” – 1 John 2:16; Ephesians 2:2-3