Unfaithful creatures! Do you not know that friendship with the world is enmity with God? Therefore whoever wishes to be a friend of the world makes himself an enemy of God.
John 15: 19
If you were of the world, the world would love its own; but because you are not of the world, but I chose you out of the world, therefore the world hates you.
2 Tim 2: 4
No soldier on service gets entangled in civilian pursuits, since his aim is to satisfy the one who enlisted him.
1 John 2: 15 - 17
Do not love the world or the things in the world. If any one loves the world, love for the Father is not in him. 16 For all that is in the world, the lust of the flesh and the lust of the eyes and the pride of life, is not of the Father but is of the world. 17 And the world passes away, and the lust of it; but he who does the will of God abides for ever.
2 Cor 6: 14 - 17
Do not be mismated with unbelievers. For what partnership have righteousness and iniquity? Or what fellowship has light with darkness? 15 What accord has Christ with Be'lial? Or what has a believer in common with an unbeliever? 16 What agreement has the temple of God with idols? For we are the temple of the living God; as God said, 'I will live in them and move among them, and I will be their God, and they shall be my people. 17 Therefore come out from them, and be separate from them, says the Lord, and touch nothing unclean; then I will welcome you.'
Eph 5: 11
Take no part in the unfruitful works of darkness, but instead expose them.
Romans 12: 2
Do not be conformed to this world but be transformed by the renewal of your mind, that you may prove what is the will of God, what is good and acceptable and perfect.