You adulterous people, don't you know that friendship with the world means enmity against God? Therefore, anyone who chooses to be a friend of the world becomes an enemy of God.
John 15: 19
'If you belonged to the world, it would love you as its own. As it is, you do not belong to the world, but I have chosen you out of the world. That is why the world hates you.'
2 Tim 2: 4
No one serving as a soldier gets entangled in civilian affairs, but rather tries to please his commanding officer.
1 John 2: 15 - 17
Do not love the world or anything in the world. If anyone loves the world, love for the Father is not in them. 16 For everything in the world - the lust of the flesh, the lust of the eyes, and the pride of life - comes not from the Father but from the world. 17 The world and its desires pass away, but whoever does the will of God lives forever.
2 Cor 6: 14 - 17
Do not be yoked together with unbelievers. For what do righteousness and wickedness have in common? Or what fellowship can light have with darkness? 15 What harmony is there between Christ and Belial? Or what does a believer have in common with an unbeliever? 16 What agreement is there between the temple of God and idols? For we are the temple of the living God. As God has said: I will live with them and walk among them, and I will be their God, and they will be my people. 17 Therefore, Come out from them and be separate, says the Lord. Touch no unclean thing, and I will receive you.
Eph 5: 11
Have nothing to do with the fruitless deeds of darkness, but rather expose them.
Romans 12: 2
Do not conform to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God's will is - his good, pleasing and perfect will.