You probably know someone who once lived passionately for Christ but has now abandoned him altogether. Your heart sinks and twists even to hear his or her name.

Perhaps even more painful than loved ones who have consistently rejected Christ for years are loved ones who seemed to have been saved at one time, only to fall away from the faith. You saw their eyes light up with love for Jesus, and then watched a dark cloud slowly roll in and cover them again. You prayed, and watched, maybe even wept, feeling powerless to reverse their course.

The apostle Paul wrote about that kind of pain in Philippians 3:17–21. Many, especially recently, have used these verses to remind us that we are citizens of heaven, and not first and foremost Republicans, Democrats, Americans, or any other kind of earthly citizen. That is a good, relevant, and needed application, especially today. But Paul was not writing here simply to warn people in love with politics, but people in love with themselves and this world. He wants us to be citizens and servants of heaven, not citizens and servants of self — to see the world as purchased, but unconquered real estate for Christ and his kingdom, not as a playground for our selfish desires.

A certain kind of Christian lives for God, dies to self, and lives forever. Another kind of “Christian” ultimately lives for self, enjoys this world for a few decades, and then dies forever.

Who Are the Enemies of Christ?

Paul exhorts the believers in Philippi, “Brothers, join in imitating me, and keep your eyes on those who walk according to the example you have in us. For many, of whom I have often told you and now tell you even with tears, walk as enemies of the cross of Christ” (Philippians 3:17–18). Who are these enemies of Christ?

“Paul’s tender, broken heart bears the aching aroma of love lost, not sustained indifference or disdain.”

I doubt that they are just worldly people who hate Christianity and do whatever they can to belittle Jesus and stifle his influence. The familiarity (“of whom I have often told you”) and tenderness (“and now tell you even with tears”) suggests another explanation. These enemies of Christ likely have professed faith in him at some point in their lives. Maybe they’re even professing faith in him now. Either way, they are suicidally rejecting him by how they live (they “walk as enemies”). Paul’s tender, broken heart bears the aching aroma of love lost, not sustained indifference or disdain.

So, if these enemies previously had been beloved “brothers” and “sisters,” what could have led them away from the stunning beauty and captivating grace they once loved? And are we in danger of following in those same drunken and destructive footsteps? Here are four questions to ask yourself about your Christianity.

1. Is your mind set on this life, or the next?

Christians who are not truly Christians are fixated on the best things in this life, rather than on the best things in the universe: “with minds set on earthly things” (Philippians 3:19). You might give your attention to a thousand different things on any given day — work, laundry, sports, children, shopping, whatever you spend time thinking about — but where does your mind default most? Which things in life not only get your attention, but your affection with it?

Many wander from Jesus because he never had first place in their hearts. He simply complemented or facilitated things they wanted more than him. Or perhaps he had been first, but the cares of this world eventually surpassed him (Mark 4:19).

The kind of Christian who will live with Christ forever in the next life is joyfully preoccupied with him today in this life. “Our citizenship is in heaven, and from it we await a Savior, the Lord Jesus Christ” (Philippians 3:20). We do not spend this life trying to experience as much pleasure as possible in this world. We spend this life waiting to experience the most pleasure conceivable (and more) there.

2. How do you deal with guilt and shame?

Christians who are not truly Christians “glory in their shame” (Philippians 3:19). God defines evil for us when he says, “My people have committed two evils: they have forsaken me, the fountain of living waters, and hewed out cisterns for themselves, broken cisterns that can hold no water” (Jeremiah 2:13). Evil is rejecting the only true fountain of peace, life, and joy, and preferring to try and create the peace, life, and joy in some other futile way.

The “Christians” Paul describes, though, mount a second assault against God and his holiness. They do not only forsake God for their cisterns, welcoming guilt and shame. They take pride and pleasure in what should be shameful. They witnessed Jesus go to the cross for their sin, despising the shame (Hebrews 12:2), and they adored their shame.

They may have professed faith in Christ and yet boasted about their sin publicly (many do). Or they fooled themselves into thinking they could do all the right things publicly, but nurture a secret affair with sin. They loved their shame, even if they were not ready to love it in front of others.

But we, instead, await a Savior (Philippians 3:20) — someone pure enough and strong enough to bear our shame and cancel our sin. With broken hearts, we confess our shame and hope in Christ, our Redeemer. We feel the awful weight of our sin, and wait with anticipation for Jesus to return and give us sinless, shameless bodies (Philippians 3:21).

3. Are you driven by selfish desires, or by God’s desires?

Christians who are not truly Christians consistently surrender to their own sinful desires. “Their god is their belly” (Philippians 3:19). Paul is not talking about food. Maybe he would, if he lived in America today. He is talking about slavery to any of our impulses — for food, for sex, for fame, for clothes, for whatever we each want. People consumed by their natural desires to consume end up without Christ.

“He is not simply a Savior to us, but also Lord and Treasure.”

At the end of the day, they worship themselves, and not God. And because they worship themselves, and not God, their impulses win over God’s warnings and promises in the moment of temptation. They know what’s best for them, but lack the courage and self-control to resist and wait. Over and over again, they surrender the fullest happiness possible for a quick, easy, temporary high.

We, instead, submit ourselves and our happiness to “the Lord Jesus Christ” (Philippians 3:20). He is not simply a Savior to us, but also Lord and Treasure. We die to ourselves — our sinful desires, our impulses, our glory — to worship God and pursue his glory. We know the temporary pleasures of food and sex and money look more satisfying than they are and pale in comparison to all we have in Christ. We surrender some thin pleasures now to have full, thick pleasure forever.

While others live believing, I am most satisfied in life when God gives me what I desire most, we live instead knowing, God is most glorified in us when we are most satisfied in him.

4. Do you live in light of the coming judgment?

Christians who are not truly Christians do not fear the consequences of their sin. They live as if they will not be judged, but “their end is destruction” (Philippians 3:19). They think the cake will never end, but before long, they’ll be staring at an empty plate. The real tragedy is that, on that day, they will wish they had nothing. Nothing will look like paradise compared to the awful punishment they face (Luke 16:24).

True Christians know that their sin — every wayward thought or deed — will be judged by an all-knowing, all-just, and all-powerful God. Paul writes, “Do not be deceived: God is not mocked, for whatever one sows, that will he also reap. For the one who sows to his own flesh will from the flesh reap corruption, but the one who sows to the Spirit will from the Spirit reap eternal life” (Galatians 6:7–8). Every sin — every seed sown to corruption — will fall, either on Christ, or on us — and we do not take that distinction for granted.

We draw near with confidence to the throne of grace (Hebrews 4:16), and by that grace, we work out our salvation with fear and trembling (Philippians 2:12). There is nothing cheap or cavalier about true forgiveness. It creates a passion for godliness and a hatred for ungodliness in the hearts of the forgiven.

God’s grace creates an intense longing to be more like him. We groan over our sin, while we wait with enthusiasm for the return of our Christ, “who will transform our lowly body to be like his glorious body, by the power that enables him even to subject all things to himself” (Philippians 3:21).

The kind of Christian who will spend eternity with Christ thinks more and more about Christ, feels more and more conviction over sin, trusts more and more that God knows what will make us happy, and fears more and more doing anything that might disgrace his grace.