Suppose someone who had never heard of Christianity approached you with this question: What are you talking about when you say you are a Christian? How would you begin? What are the basic essentials? How would you explain a basic doctrine like one God and three persons?
I have given some thought to these questions and my mind is boggled by the prospect of such a challenge. Ordinarily, we assume people have been exposed to some teaching or witness that provides at least a backdrop for dealing with spiritual truths. This is not necessarily true.
I am a Christian because of a person and a truth I cannot logically prove. I think I would endeavor to lay a foundation under my beliefs by asking an inquirer if there was something in which he believed that he could not prove. I would remind an individual that much of what we consider real is highly subjective.
An imperfect example, but somewhat comparable, is feeling an electrical current. Someone standing beside you may not feel anything. You cannot explain this sensation or prove the reality of your physical tingling. You know it is true because you feel it and it has an effect upon you.
At some point, I would endeavor to explain there are some things we believe that we cannot scientifically prove. We call this faith. One of the writers of a book we consider divinely inspired said, “Faith is the substance of things hoped for; the evidence of things not seen. (Hebrews 11:1)
I am a Christian because I believe the God/man, Jesus, is God in the flesh. I believe by faith, the narratives that tell of his birth, his life, his death, his resurrection and his promise to believers. This is a truth I cannot take to the laboratory and prove. I just believe it, and I am convinced beyond the shadow of any doubt it is absolutely true.
On a very personal level, I experience the presence of God in my daily life. I believe God became one of us in the person of Jesus Christ for the purpose of verifying his love. Today, God is a spirit. We call Him the Holy Spirit, and, when allowed, indwells believers at all time. He provides guidance, encouragement, consolation, inspiration, power and discernment.
Dear friend, I have tried to explain Christianity from my experience; hopefully, this has been most helpful in your understanding of the Christian doctrine. It is my prayer, you will believe by faith and will receive the person of Jesus Christ as Lord of your life.