We Christians can so often be more worldly than not - Christians more focused on secular pursuits rather than the pursuit of Christ. And although we can be a Christian in a secular field, we don't have to be outside the church to be worldly.
Secular Christians fail to live out the life that God intended for them. While they say they have received Christ, they fail to follow Him fully, and are thus a people who don't live out their real identities in Him. This kind of life is not what God wants for us.
It's very dangerous to be a secular Christian. The Lord Jesus said we are not of this world though we live here (see John 17:16). God wants us to strive to be holy because He is holy (see 1 Peter 1:16). He wants us to be separate from the world (see 2 Corinthians 6:17).
We need to know if we're becoming more of a secular Christian than a Christ-following Christian. As I said earlier, it's not whether we have a secular career or not; it's about the heart.
Signs you are a secular Christian
To help us see if we're becoming more set apart for God, or worldly and secular, here are a few signs identifying a secular Christian.
1) A heart that longs for worldly gains more than eternal gains
The first telling sign of worldliness is - you guessed it - worldliness. If we love the things of the world more than the things of our God, then there's something very telling there.
1 John 2:15-17 warns us,
"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. For all that is in the world—the lust of the flesh, the lust of the eyes, and the pride of life—is not of the Father but is of the world. And the world is passing away, and the lust of it; but he who does the will of God abides forever."
2) A religious form without the power to change a life
Next, secular Christians appear Christian, but don't have the power to live a changed life. They can go to church and even speak Christian jargon, but unless they have repented of their sin and have the Spirit of God sanctifying them, they will never have a changed life.
Paul warns us about this in 2 Timothy 3:2-7, saying:
"For men will be lovers of themselves, lovers of money, boasters, proud, blasphemers, disobedient to parents, unthankful, unholy, unloving, unforgiving, slanderers, without self-control, brutal, despisers of good, traitors, headstrong, haughty, lovers of pleasure rather than lovers of God, having a form of godliness but denying its power. And from such people turn away! For of this sort are those who creep into households and make captives of gullible women loaded down with sins, led away by various lusts, always learning and never able to come to the knowledge of the truth."
3) A focus on humanistic "good morals" rather than God's word
Lastly, secular Christians have a focus on rules that appear to have common sense and might even sound "Biblical," but such rules can never change the heart. Only the word of God, revealed by the Holy Spirit, can make a person see the error of his ways and thus change him. Lists of humanistic "good moral" rules can never do that.
Colossians 2:20-23 tells us,
"Therefore, if you died with Christ from the basic principles of the world, why, as though living in the world, do you subject yourselves to regulations - "Do not touch, do not taste, do not handle," which all concern things which perish with the using - according to the commandments and doctrines of men? These things indeed have an appearance of wisdom in self-imposed religion, false humility, and neglect of the body, but are of no value against the indulgence of the flesh."
These three aren't the only signs the Bible gives us, but I believe these are the most telling of all. Anybody can go to church and speak Christianese, but not everyone who calls himself a "Christian" really does follow Christ. Jesus Himself told us this truth, and we better heed it:
"Not everyone who says to Me, 'Lord, Lord,' shall enter the kingdom of heaven, but he who does the will of My Father in heaven. Many will say to Me in that day, 'Lord, Lord, have we not prophesied in Your name, cast out demons in Your name, and done many wonders in Your name?' And then I will declare to them, 'I never knew you; depart from Me, you who practice lawlessness!'" (Matthew 7:21-23)