Philip. 2:1-4 (ESV)
So if there is any encouragement in Christ, any comfort from love, any participation in the Spirit, any affection and sympathy,  complete my joy by being of the same mind, having the same love, being in full accord and of one mind.  Do nothing from rivalry or conceit, but in humility count others more significant than yourselves.  Let each of you look not only to his own interests, but also to the interests of others.
“Complete my joy by being of the same mind,” I think if there is one thing that would vex Paul more than anything were he to see the church today it would be doctrinal antinomianism. By doctrinal antinomianism I do not mean the doctrinal error of antinominanism that most doctrinal antinomians despise, but the complete disregard for doctrine that runs rampant in the church today. It is curious that we have a whole subculture of “evangelicals” as they are called in America, (That despite their propensity to be anything but evangelical. I’ll pick this train of thought up again in a minute.) who will argue tooth and nail for the inspiration and inerrancy of the bible and yet don’t give two figs about what it says concerning women’s ordination, Baptism, the Lord’s supper, the Trinity, or Justification by faith alone. Anytime these subjects are brought up you get a response of “well that is your opinion and you are entitled to it, but I read it this way and it doesn’t matter.” Or my personal favorite “well we can’t possibly know the whole truth, we see through a glass darkly.” Who said anything about the whole truth, or the fullness of it? I am talking about that bit of truth that God has so deemed necessary for us to know that he has clearly expounded upon it in scripture. That we will understand things better in the here beyond does not negate that God has told women to be silent in the churches (1 Cor. 14), told parents to baptize their children (Acts 2:38-39), told us it is his body and blood in the Lord Supper, which is the New Testament in his blood, not a mere covenant, (Luke 22) That he is 3 persons in 1 divine unity (Matthew 28) and that we are justified by faith, not by works, (Romans 1:16). And being justified does not mean being saved from cigarettes. You can save yourself from those without Christ. I’m much more worried about the smoke of hell. (And yes there is a hell, the bible told me so.)
What God has clearly spoken we can clearly know. And saying that we see no as if through a glass darkly to excuse the ignoring of clear passages of God’s word is a cop out, and it is just as sinful and probably more dangerous than the fact that your son is sleeping around with a girl that smokes. Not that that is not an issue you should deal with,( the fact that your son is having sex with her outside of marriage, not necessarily the fact that she smokes, which seems to be that which more evangelicals are worried about these days. ) This brings me back to the point I was making about evangelicals not being evangelical.
Evangelicals tend to actually be the opposite of evangelical. They tend to be legalists. And this normally because they don’t give to figs about doctrine, or what the Bible really says about anything. You see to be truly evangelical you have to know the Gospel, the forgiveness of sins, justification by faith alone. But the gospel is doctrinal. The Gospel deals with doctrine. Things like the Trinity, infant baptism, the Lord’s supper, even upholding the pastoral office as God gave it to us, and not abusing it with women’s ordination are most intimately connected to the forgiveness of sins, the gospel. Rules for living you can get anywhere, Dr. Laura has great advice that works for Christians, Jews, and Muslims alike. But you can’t have the Gospel if you don’t have the Trinity, or the hypostatic union of the two natures in Christ. You lose the Gospel rather quickly when you make salvation dependant on one being able to pledge themselves to Christ in baptism. Deny the body and blood of Jesus in the Lord’s Supper and you no longer have the incarnation, Christ is no longer God, and you definitely don’t have the forgiveness of sins, the gospel, if Christ is a mere man, or if it was mere man that died for you. To be truly evangelical, gospel centered, you have to be doctrinal.
This is why Paul admonishes us to be of the same mind. He is talking about doctrine, what you teach. It matters. We can’t all come together as one in Christ when we can’t agree on who he is. And the question of who he is, is a doctrinal question. Let’s stop pretending it doesn’t matter, and start giving a fig or two about doctrine. It has the ability to save you from more than cigarettes.