A longer version of this FAQ has been turned into a sermon, and is located here.
What is Doctrine?
Christian Doctrine is the summarized teachings of the Bible, nothing added or subtracted.
What about the teachings of the church?
Christ's church is defined by the scriptures, so any local church that derives its teachings from the bible will have a doctrine consistent with it. The role of the church is to serve as a vehicle for discipling people in the scriptural following of Chirst, not to create extra-biblical doctrines.
What is a Christian?
A Christian believes in the Trinity: God the Father, his Divine Son, and his equally Divine Holy Spirit. A Christian is one who has personally accepted the substitutionary sacrifice of Christ for sin on the cross and so has been redeemed, born again, baptized in the Holy Spirit, and made one of God's family for the purpose of witnessing to the glory of God and doing the works of Christ.
I thought religion was defined by what people do.
It is, but Christianity is first a faith-grounded, grace-given relationship with the Saviour. Out of that relationship flow actions or works consistent with faith. The latter constitute religion, something one can easily have without being a Christian.
What is Christian Morality?
It can be summed up in two sentences: (1) Know God by faith, learn to love him and his ways, seek to serve him, and have His Holy Spirit instantiate Christ's character in you, and (2) Love your neighbour more than yourself.
Wait. I want to be number one.
Self-fulfillment, self realization, and self-actualization--a three-self philosophy :)--is utterly antithetical to Christianity. Self-ism is a modern (new age) version of hedonism. It cannot lead to God, who will brook no idols, especially self.
How can the world be changed for the better?.
Individuals who accept by faith in Christ the power of God to change them personally are a means by which others also can be changed. Society can only be improved one person at a time from within, and the creator of the universe is the only one who has sufficient power to do this.
You propose Christian responses to ethical questions. I thought we lived in a post-Christian world.
Perhaps we live in a pre-Christian one.
I don't want Christians shoving their morality down my throat.
Let's put this one to bed for good. Christianity cannot do that, because Christian morality comes from the empowerment of the Holy Spirit working and changing from within, NOT by external force. Besides, there's no shortage of others who try very hard to shove their immorality down other's throats. Rick Sutcliffe's CSF has characters who'd like to. Just as Hitler, Stalin, Mao, Amin, Pol Pot, and otherreal world dictators and persecuters of all eras, such people usually prove to be a pretty nasty lot.
Hey, man, I'm a moral person. I'm good enough to go to heaven.
The Bible says God's standard for admission is absolute perfection, and that no one but Christ has ever achieved this, because He was God as well as man. So, it's enter on the basis of Christ's merits or not at all. He is the only way, the only truth, the only light. When a person trusts in him for salvation, God not only reckons the believer's sin nailed to the cross (punished in Christ), but he also reckons Christ's perfect righteousness as ours.
Variation--You've got your religion; I've got mine.
Strictly speaking, Christianity is not a religion, if by a religion one means a system of beliefs, practices, and rules that is supposed to produce better living, a salvation of some kind, or the reform of person or society. Rather it is a relationship with the living God (initiated by Him) that transforms a person from within. There is only one God, so there can only be one relationship with that God, and only one true religion following from that relationship.
Variation--I follow the ten commandments. I'll be fine.
The purpose of the Old Testament law was to teach us the impossibility of coming to God by a rule-based morality. It should, as it did with Moses and David, bring us to the point where we realize that law cannot do the job of making a lost human being holy. Rather, it can only point out transgressions, condemn, and dictate punishment. We can only enter God's presense by His grace.
Jesus was a good teacher. Why say more?
Why do you call Him good? No one is good but God. Jesus Christ not only claimed to be God incarnate, He backed that claim up. Either He was utterly mad, or He was Who He claimed to be. A merely "good teacher" doesn't make any sense.
How do I become a Christian?
See John 3:3, 16-17; Romans 10:9-11, Acts 16:31. You must confess you are a sinner, unable to enter God's presense on your own merit, and ask in faith that the death and merits of Christ be applied to your account so that you may be born again. God will hear your prayer and give you His salvation by His grace. The death of Christ will be counted as your punishment for sin, and His merits will be used to cloak you in righteousness so that as God looks on you He sees His son. You will become His child and He your Father. At the same time you will receive what the Bible calls "the Baptism of the Holy Spirit" which means that God makes you His temple and comes to live in you to teach you how to be like Christ.
Then, having begun the only possible way, carry on to do in the same way. (Holiness is an effect of salvation, not it's cause.) Read the Bible, saturate yourself in the word and obey it. Get baptized. Being immersed does not itself save, but is a public declaration that God has saved you. Actions flowing out of a character that is daily being transformed into Christ's will be evidence you indeed have saving faith.
What is sanctification
Sancification is another name for that ongoing process by which the Holy Spirit works in a believer's life to instantiate the character of Jesus Christ in that person--leading the believer to think and act more like Christ in the process. "Love God" and "love your neighbour" remain the operative commands, but now, with the Holy Spirit indwelling, it becomes possible to choose to do these things. It becomes possible to please God, for with all our failings, he will see his Son's righteousness in us (a) absolutely in a legal sense (b) increasingly in a practical sense.
What is the filling of the Holy Spirit?
This is not a one-time event (as our coming to salvation in faith is) but another name for sanctification. The more we surrender to the Holy Spirit on a daily basis, the more like Christ we become.
Can salvation be lost?
No. Salvation is based on God's grace and not on our works. It is not possibile for God to know absolutely one day that you are one of His redeemed, chosen in Christ from before the foundation of the world, yet to know absolutely the opposite the next day. Sin in our lives is still possible (this isn't heaven yet) but when we repent of it, God forgives us and restores the joy of fellowship with Him.
But if I can sin as a believer, how do I know I am saved?
By whether the Holy Spirit is operating within you and bring you to grief and repentance over that sin. The one who can sin deliberately, flagrently, willfully, repeatedly, even habitually, and show no remorse or sign of repentance, does not belong to God, and never has.
What should I look for in a church?
You've asked the right question, for you do need to express your Christianity as part of a fellowship of believers, to be discipled and to help make disciples. Look for a church where the Bible comes first, where human traditions and human interpretations are subject to scriptural authority, and where you can see the evidence of God's grace in action as souls are redeemed and lives are changed.
What churches should I avoid?
A Church with heavy emphasis on human leader(s), where the Bible is not regarded as authoritative, with excessive interest in your money, that demands certain works or services to gain a blessing or to earn salvation, or that emphasizes experience, this world's affairs (such as politics), emotionalism (or anything else) above faith, obedience, grace and God's Word. No, I won't be more specific. If you're serious, you can find such a church for yourself. It's not the name over the door that matters; its the Spirit dwelling in the people who make up the local church that is important.
What about revelation in creation?
Observations of Christ's creation, if properly interpreted, can illustrate Biblical truths. However, the physical universe was badly broken by the fall of Adam and Eve, and, moreover, our interpretations of it are by fallen minds. Thus, whenever there is a difference between a human interpretation of the physical world and the literal normal reading of the Bible, the latter should be taken as true.
I've heard the Bible has errors.
When documents from the first few centuries are compared, one does occasionally find what appear to be minor copying mistakes. In no instance do these affect the overall teachings of the scriptures. No doubt in anticipation of our obtuse attitude, the fundamental truths of Biblical teaching are repeated numerous times. This ensures the original infallible and inerrant Divine revelations will survive even being handled by fallible human beings.
Do Old Testament and New Testament teachings differ?
Much of the Old Testament law was given to Israel to ensure God would have a set-apart (sanctified) people. Some of that law is national or ceremonial in nature, and is not repeated in the New Testament, leading us to conclude that it was limited in scope, not universal. Moreover the New Testament teaches that law was designed not as an end in itself, but to lead us to Christ (by showing us we couldn't obey it and create our own righteousness, so were in need of His.) However, God's demand for worship and service to Him alone, the moral laws, and the principles on which they are based, are all repeated in the New Testament. Right and wrong (in the moral sense) is defined by the very character of God, and so cannot change. It is our failure to love God above all else, love our neighbour as ourselves, and obey God's moral law that condemn us as sinners and demands the death penalty against us--a penalty executed instead against Jesus the Christ. Those in Christ have the Holy Spirit and the Scriptures to teach them what is right.
Will my sanctification ever be complete?
Not in this life. However, when Christ takes us into his presense, either when we die, or when he comes for His church, we will become fully like him, because we will see him face to face. After that, it will be impossible for us to sin, to worry, to displease him in any way. Meanwhile, when a believer sins, confession and repentance always bring forgiveness. Moreover, because Christ is the guarantor, a believer's sin, though it surely breaks fellowship, grieves God, and causes a loss of some eternal reward, it does not cancel our salvation. The latter depends on Him, not on us. Otherwise, it would come from works, not grace.