What Makes a Christian?
People often make the claim that they are Christians. But what do they really mean by that? Is it the fact that they live in America or were born to Christian parents, and that makes them a Christian? Is it that they think Jesus was a pretty cool sage and teacher, and they like some of his sayings? Is it because his name is used in the title of some organization that they belong to? Or is a Christian a true follower of the teachings of the Jewish Messiah, Jesus?
Authority
The New Testament (NT) is a God-inspired collection of documents written based on eyewitness testimony about the historical Jesus, recorded within the lifetime of the apostles. These men walked with him, were discipled by him, witnessed (or talked with people who were actually there) his miracles and his resurrection, and many of them gave their lives to spread the truth of the Gospel of Jesus Christ. Historic Christianity sprang from the real person, Jesus, and actual events of his life and teachings. These documents, and the foundational Old Testament (OT) scriptures, are collectively called the Bible, and are the sole authoritative sources for what it means to be a Christian.
So what does the NT say that a Christian is? Let's start with Jesus himself,
So Jesus said to the Jews who had believed him, “If you abide in my word, you are truly my disciples, 32 and you will know the truth, and the truth will set you free.”
John 8:31-32
The word "abide" means to follow, live out, and hold to his teachings. As he said, it is more than just verbally saying that you follow him or simply believing that he existed as a man. These early disciples of Jesus were called Christians by both the church and by the world around them. The NT is the one and only place to be sure of what he taught. You don't get that authority from a pope, a modern prophet, a pastor, or even the internet.
The apostle Paul had this to say about what was taught by the early church shortly after the Resurrection,
Now I would remind you, brothers, of the gospel I preached to you, which you received, in which you stand, 2 and by which you are being saved, if you hold fast to the word I preached to you—unless you believed in vain. 3 For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, 4 that he was buried, that he was raised on the third day in accordance with the Scriptures, 5 and that he appeared to Cephas, then to the twelve. 6 Then he appeared to more than five hundred brothers at one time, most of whom are still alive, though some have fallen asleep. 7 Then he appeared to James, then to all the apostles. 8 Last of all, as to one untimely born, he appeared also to me. 9 For I am the least of the apostles, unworthy to be called an apostle, because I persecuted the church of God.
1 Corinthians 15:1-9
One cannot rightly be called a faithful follower of Jesus Christ (i.e. a Christian) without affirming this. Just like one can call themselves a woman, when they are really a man, people can call themselves Christians, and not actually be one themselves.
Essential Terms and Concepts
Let's be really clear about what scripture means when it uses some of these terms. It is disingenuous to say that you believe these things, but then to misleadingly change them to mean something other than the usage meant by the authors. One cannot be a Christian, as meant by the disciples and by Jesus himself, without affirming these truths.
God
The one true God who is the Creator of all things. He is the all powerful, all knowing, self-existent (was not created), eternal, all good, and omnipresent being. There are no other true gods, in the multiverse or beyond (sorry Thor). The Bible also clearly teaches that the Father is God, the Son (i.e. Jesus, the Word) is God, and the Holy Spirit is God. Together they are One in essence and being, and yet they are distinct persons. God was never a man (a created being), nor can a created being (man) ever become God. There is, and only can be, one necessary being who is the greatest conceivable being – in other words, God. This is what is meant by the term, trinity, which is shorthand for the reality of One God in Three distinct Persons. To deny this view, is to reject the God of authentic Christianity. All others are false.
Christ / Messiah / Jesus
The Jews were promised a Messiah (or Christ in Greek) who would be a descendent of King David. Both the OT and NT describe him and show that only one person fits the criteria, and that person was Jesus of Nazareth. He was born of a virgin, through the supernatural act of the Holy Spirit (not physical sex, whether by a man or a god). He lived a sinless life, performed supernatural miracles, fulfilled past prophecies about himself, including being crucified and bodily resurrecting on the 3rd day. He did this to pay the price of the sins of those who are willing to accept him as Lord and Savior. This is the real Jesus. All others, even if called by this name, are imposters. Only this Jesus is the Savior.
Jesus is the God-Man. He is uniquely fully God and also fully human. He was not a created being, as claimed by some, nor is he an exalted man who became God. He existed from the Beginning and, as God, is the Creator of all things that were created. He is not a spirit being, created by God, and is not an angel or an exalted human being.
Resurrection
While someone can make great claims to deity and/or miracles, Jesus proved it by being raised from the dead. Not as a spirit being, not in some metaphorical sense, but into a physical resurrected body. The Bible makes the claim that he was raised from the dead by God, recorded separately in the Bible as done by the Father, and by the Son, and by the Holy Spirit. As believers, we have the promise of resurrected bodies as well.
Disciple
This is a believer in Jesus Christ who faithfully follows and obeys his teachings. It does not apply to people who just give lip service to Jesus, or who think he was a guru with good teaching. It does not mean someone who is a member of a church, a club, or a denomination. It also does not mean someone who sincerely believes in a Jesus who is not the one identified in scripture as the Messiah.
Teachings
Jesus taught many things to his disciples and all the important ones were written down and recorded in the NT so that we could believe and follow him with all our heart, and soul, and mind, and strength. There are no secret teachings that are only available to next-level followers, nor are there additional authoritative writings that change or update what he expects from his followers. These scriptures are sufficient to provide all that we need to know about living as he did and how to be saved from our sins.
Scripture / Bible
Together the OT and NT documents are the sole authoritative sources of Special Revelation from God, which was given by God alone through divinely inspired men of God, and by Jesus himself. In addition, there is General Revelation that is available to all people through the creation and our inbuilt conscience as beings created in the image of God. While there are a great many writings about Christianity, morality, ethics, and church doctrines, none have the God-breathed authority of biblical scriptures. Anything or anyone who teaches something other than (i.e. contradicts) what is found there, is a false teacher with man-made doctrines.
Because of modern manuscript evidence and studies, we have high confidence in the actual words originally written by the inspired authors. The true Gospel, according to their own words, has not been lost. Most modern translations (including the KJV), are faithful to the original texts, with minor variations that have no impact on the core teachings of Jesus and the apostles. There are dangerous mistranslations (e.g. The New World Translation of the Jehovah Witnesses), and also some paraphrased versions that read easier, but have theological interpretations and opinions added. Reliable modern versions would include ESV, NASB, NIV, or NET.
The Gospel / Salvation
It is not complicated, but not so easy to embrace since it requires starting a new journey with no promises that it will be struggle free. Above, I shared what Paul said. Here is another way to put it:
The eternal triune God created all things, including man and woman.
They rebelled and sinned against God, with the penalty of death and eternal separation from their Creator.
God provided a way to be reconciled to Himself, by becoming the God-Man, and lived, died, and rose again to pay the debt we owed.
We are saved by repenting, confessing our sins to him, and then putting our trust (belief, faith) in what God has done, in our place, for the forgiveness of our sins. It is not based on anything we can earn, but is a gift of God. This is solely through the real Jesus, by identity and not just by name.
Those saved become new creations in Christ, and receive eternal life.
For it is by grace you have been saved, through faith—and this is not from yourselves, it is the gift of God— 9 not by works, so that no one can boast. 10 For we are God’s handiwork, created in Christ Jesus to do good works, which God prepared in advance for us to do. Ephesians 2:8-10
Works never earn your salvation, but are things you do because of your response to him and your obedience to his commands. You cannot earn your way into heaven by doing more good than bad. You do not earn degrees of exaltation in Heaven or on earth by anything you do. Works come as a result of faith, not vice versa.
TLDR
A Christian is one who is a disciple of the historical Jesus Christ found in the authoritative OT/NT scriptures.
A claim to be a Christian is not a sufficient reason for it to be so. While people are free to call themselves anything they wish, they cannot force others to agree.
A Christian is not someone who denies fundamental beliefs of the Church founded by Jesus, but is one who believes and does as Jesus taught. Using the same words, but holding to a different definition, does not count as belief in historic Christianity.
Jesus is the God-man, part of the eternal Triune God of Father, Son, and Holy Spirit.
There is only one true God, and all other claims are false. Men cannot become God, nor was God ever an exalted man.
