1 John 2:15-16
15 Do not love the world or the things in the world. If anyone loves the world, the love of the Father is not in him.
16 For all that is in the world— the desires of the flesh and the desires of the eyes and pride in possessions—is not from the Father but is from the world. ESV
Romans 12:2 Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect. ESV
Romans 12:2 Do not be conformed to this world (this age), [fashioned after and adapted to its external, superficial customs], but be transformed (changed) by the [entire] renewal of your mind [by its new ideals and its new attitude], so that you may prove [for yourselves] what is the good and acceptable and perfect will of God, even the thing which is good and acceptable and perfect [in His sight for you]. AMP
“By the world understand everything connected with the present life, apart from the kingdom of God and the hope of eternal life. So he includes in it corruptions of every kind, and the abyss of all evils. In the world are pleasures, delights, and all those allurements by which man is captivated, so as to withdraw himself from God.”
Charles Spurgeon on Romans 12:2
Then come ye out from among them, and be ye separate, and touch not the unclean thing. Would you attain the full assurance of faith? you cannot gain it while you commune with sinners. Would you flame with vehement love? your love will be damped by the drenchings of godless society. You cannot become a great Christian—you may be a babe in grace, but you never can be a perfect man in Christ Jesus while you yield yourself to the worldly maxims and modes of business of men of the world. It is ill for an heir of heaven to be a great friend with the heirs of hell. It has a bad look when a courtier is too intimate with his king’s enemies. Even small inconsistencies are dangerous. Little thorns make great blisters, little moths destroy fine garments, and little frivolities and little rogueries will rob religion of a thousand joys. O professor, too little separated from sinners, you know not what you lose by your conformity to the world. It cuts the tendons of your strength, and makes you creep where you ought to run. Then, for your own comfort’s sake, and for the sake of your growth in grace, if you be a Christian, be a Christian, and be a marked and distinct one. (from Spurgeon’s Morning & Evening)