God, not the world, must have first place in His children’s hearts. (Matthew 10:37; Philippians 3:20) We must remember that what God is against here is not planet Earth, but the invisible, spiritual system of evil dominated by Satan. This world system keeps people in bondage, blinds their hearts, and opposes God and all that belong to Him.
I appeal to you therefore, brothers, by the mercies of God, to present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship. 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. (Romans 12:1-2 ESV)
One of the markers of Christian genuineness is separation from the World. This isn’t a physical removal from planet Earth or a disintegration of the body of a Christian. A genuine Christian’s character should be in a continual upgrade unto Christlikeness. That means that as he or she cooperates with God in their sanctification, working out their salvation with fear and trembling, their character will take on more and more of Christ’s character. They will love what He loves and hate what he hates. God is love, but He hates a certain type of love.
If the world hates you, you know that it has hated Me before it hated you. 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, because of this the world hates you. John 15:18-19 (NASB)
Do not love the world nor the things in the world. If anyone loves the world, the love of the Father is not in him. For all that is in the world, the lust of the flesh and the lust of the eyes and the boastful pride of life, is not from the Father, but is from the world. The world is passing away, and also its lusts; but the one who does the will of God lives forever. 1 John 2:15-17 (NASB)
If professing believers love the very thing that hates the truth of God’s sovereignty, His genuine character–not the one they have made up, and all genuine Christians who proclaim these truths then they prove either that they are very immature Christians or the love of the Father is not in them. The word “love” used here, in the Greek, means “affection and devotion.” John is telling us that genuine Christians will not habitually have affection and devotion for the world or the things in the world.
I know many professing Christians who believe that death is a tremendous tragedy. They love their life here more than anything else. They pursue entertainment in everything they do seeking to be fulfilled in sports, or movies, or recognition for working hard in church. On the other hand, John tells us in the passage from 1 John that if we habitually love the world like that then we are in the process of revealing that we are disingenuous Christians.