[Part I, which lays out basic Christian teaching, is here.]
Christianity is not like any other thing you can join.
You join other things because they are enjoyable, or beneficial, or their cause is important to you. Otherwise, you have no reason to join.
Granted that it can be enjoyable, beneficial, or an important cause, Christianity is not like other things you can join. When it comes to ultimate issues, the criteria for joining a thing are different.
There are two basic reasons why you should join Christianity. One, unless your sins are forgiven you face eternity in hell, and forgiveness of sins comes only through Jesus of Nazareth. All humans live forever, but some live forever in a bad place.
The other reason is this: The completely true description of what reality is and how it operates comes only from Christianity, because God revealed this knowledge in the Bible. When a society rejects Christianity (as ours is doing) it cannot function correctly (as ours increasingly does not.)
A non-Christian society can sometimes function adequately, based on its partial understanding of reality that man can attain because he is made in the image of God and is therefore capable of grasping many truths. But America lacks even this pagan common sense. Our rulers are anti-reality, not just non-reality, in their basic orientation. We need the sanity (to say nothing of the wisdom) that comes only from Christianity.
True knowledge of how reality operates includes knowledge of the proper operations of the individual person, the family, and the society. To fix our nation we need to know how people and nations properly operate. If you’re going to fix things you must know how they’re supposed to be. And who would know how they’re supposed to be? Only the Creator of reality, or anyone who knows what this Creator has revealed in written form, in the Bible.
Atheists believe there is no manual of operation because reality has no Manufacturer. This belief is mistaken. Reality must have a Creator because nothing is self-creating. The Creator has always existed, because nothing else is available to create Him and because there must be something that is eternal. If nothing is eternal then everything had a beginning and there was a time when nothing was. But if nothing was, nothing could come to be, because a state of nothingness cannot give rise to anything.
Therefore the Creator has always existed. But the reality we can directly observe has not always existed and therefore Something created it. This is why the Creator necessarily exists. Therefore the only question for those who want to know how reality operates is whether this Creator has spoken to us.
He has spoken, in the Bible.
Members of other religions deny that the Bible is from God. There is proof that the Bible is from God, but the proof is not quick. Here is a summary.
If the Bible were from God how would it be possible to know this? Not easily. You cannot just look at the copyright page (“Copyright 95 AD by God, all rights reserved”), nor can you simply assume, as atheists do, that God does not exist. Nor can you just hunt for errors, because to know that something is an error you must know the truth about it already, which is to assume that the Bible is not God-breathed, which is to assume your answer, not prove it.
Another approach is needed.
When it comes to judging ultimate issues, we must judge the system as a whole. This principle is well-known in science. We judge a scientific paradigm by its internal consistency and its ability for account for more known facts than any rival theory. Every scientific theory has anomalies (unexplainable / unexpected things), but the best overall theory is accepted as basically correct.
A similar approach is needed when we judge our religion. Christianity is internally consistent (meaning that you cannot derive a contradiction from its basic principles) and it does a better job of accounting for the facts we see than rival worldviews. This is why it is to be believed. And Christianity comes from the Bible.
There are other reasons to accept the Bible. When we can independently verify what it describes, we find the accounts are accurate. It has a unity unparalleled among other religious books. Its system is satisfying and compelling. The person of Jesus Christ whom it describes is forceful and wise. These are only some of the reasons.
As I said, this is a summary, not a complete proof. Ultimate reality cannot be wrapped up neatly in a few paragraph.
We have no choice but to judge systems. Since man is not omniscient he cannot just intuit the right framework of thought and then spend the rest of his life operating within it. The world presents us with many competing systems of thought but there is no universally agreed-upon Manual of Thought that will tell us which system is correct. If God exists then there will be an optimal system, because reality will be a certain way and not another way. But each of us is capable of being wrong so we need to test our way of thinking.
(Many people do not test their thinking. They go with the system they like best. They go with their intuition. Sometimes people intuit right, sometimes they intuit wrong. Your odds are better if you test your system.)
Of course, our worldview colors our interpretation of the facts. Atheists fail to see many facts that theists are able to see. (The reality of sin, for example.) That’s why you need to be aware of your worldview so that you can test it.
That’s the second reason why you should join Christianity: It’s true.
So what is this Christianity and where can it be found? Inquiring minds want to know, because all good things have counterfeits.
To know what it is, read the words of its founders. Jesus is the one Founder, but He also trained assistant founders and His spoken words, and the writings of His assistants, are found in the New Testament.
And the New Testament declares the Old Testament also to be the Word of God. The whole Bible is the manual of Christianity.
There is controversy about the correct way to interpret the Bible. You will have to choose a side. But consider this: Authors of books usually intend that normal people can understand the main meaning without the need for an expert to supply an esoteric meaning that a normal person would never discover on his own.
So it is a good assumption that the Author of the Bible intended that normal people of the time and place where each of its parts were written would be able to understand the basic meaning without an esoteric interpretation being supplied by an elite.
Our society is different from the societies in which the Bible was written, so experts in the ancient world and its languages may occasionally be needed for us to understand the exact meaning of a biblical passage. But the expert’s knowledge is pubic knowledge, based on public data. He does not supply an esoteric interpretation.
So find the straightforward meaning of a text, by consulting Bible commentaries or competent Bible teachers if necessary. If experts disagree, consider which expert makes the most convincing case, all evidence being considered.
Then make your choice and take your stand.