So exactly what is Christianity about? Here is a quick introduction to people who may have vaguely heard about Christianity, or who have not heard of it at all. Christianity is based on an important compilation of documents called the Bible, which was written over many hundreds (even thousands) of years. Christians believe that the Bible is completely inspired by God, and so we can trust everything it says. The Bible will be my main reference for the rest of this article. Bible references are given in the form (Book Chapter:Sentence) so that you can look them up for yourself in the Bible, if you want.
The Bible in 1 Sentence
Did you know the entire Bible can be summed up in one sentence? In the Bible, it says "God loved the people of this world so much that he gave his only Son, so that everyone who has faith in him will have eternal life and will never really die." (John 3:16). However, while this is simple, it does miss some details which are important. Let's go into a little more detail so that this makes more sense.
The Main Points of the Bible
The Bible is a very large book, and contains many things - history, poetry, instructions for everyday living, and even predictions about the end of the world! However, it focuses on a few main themes which are indicated below:
God created the universe, and also created you!
At the very start of the Bible, it tells the story about how God created the world (Genesis 1 and 2). God is outside of space and time, and so he existed even before the Big Bang. In fact - God caused the Big Bang! God is so powerful that he created the universe just by his will, and he shaped and created Earth specifically to be a home for humans and animals. God made the first people - Adam and Eve - and gave them a place to live in called the Garden of Eden. God made people so that he could love them, and so they could love God back. Did you know that's why God made you? God made each and every one of us special, and knows everything about us - even how many hairs are on your head! (Matthew 10:30). God loves you more than anyone else in the entire world loves you, and wants you to love him back.
People have Sinned
Ever since God made people, people were given free will. This is because love is really only valuable if love is freely chosen and not forced. However, the very first two people (Adam and Eve) decided to do something that God told them not to do. Not obeying God is called "sin", and causes our relationship with God to be damaged. When Adam and Eve sinned, they lost their close relationship with God, and also caused all of the universe to fall under the curse of entropy. God warned Adam and Eve that this would happen, but they did it anyways. Now everyone will die, and there is decay, disease, and evil in our world. Since Adam and Eve were our ancestors, every one of us has inherited the tendency to sin. God warned that sin causes death, and if we die with sin then we will be forever separated from God. This eternal separation from God is called "hell".
God sent Jesus to Rescue us from Sin
God knew that Adam and Eve would sin, but this was a result of their free will which God had given them. However, God loved people so much that he doesn't want us to end up permanently separated from him. So God created a way out - a way to pay for everyone's sins so that after we die we can come spend eternity in heaven, with God. Heaven is a perfect place where there will be no sin or evil or death, and people will be completely happy, and it will last forever. God's rescue plan was to send Jesus. Jesus was "God's Son" - not biologically, but Jesus was actually part of God himself, that came to experience life as a human being approximately 2000 years ago.
Because Jesus was God, he was perfect and never sinned. God said the penalty for Sin was death, and so sin could only be erased/paid for with death (Romans 5:12). Jesus came to die in our place - he did not deserve death because he had never sinned, and so his death can count as payment for all of our sins instead! (Romans 4:25). We just have to tell God that we believe Jesus really was God, and that we accept Jesus' payment in our place (Romans 10:9). Then all our sins are paid for, and when we die we can go live with God in heaven forever.
No one is good enough to earn going to heaven on our own (Romans 3:10). Even the best things we do are like "dirty rags" compared to God's perfection (Isaiah 64:6). We are held up to the standard of God's perfection, not to our human ideas of "good enough". This is why even if you lived a life as good as Mother Theresa, you would not be able to go to heaven without Jesus. The only way to get to heaven is to believe in Jesus' death for your sins (Romans 4:4).
How does God want us to live?
A large part of the Bible explains how God wants us to live. We are told not to kill others, not to steal, not to worship other things besides God, etc. However Christianity is not just a list of "do not's". There are many things God wants us to do. God wants us to love him with all of who we are. That means we should love him in our hearts, think about God in our heads, thank him for all the good things in our lives, and to thank him for sending Jesus to rescue us. We can try to please God by living properly and not sinning, but God knows we will still mess up. God wants us to encourage and love others (even our enemies), care for poor and sick people, love people who are not loved, and stand up for what is right (Romans 12:9-18). God also wants us to tell others about him, so that they can believe in Jesus too!
Jesus is Coming Back!
However, the really good part of the story is that Jesus didn't just die - he also came back to life! This proves Jesus was really God, and does have power over death. After he came back to life, Jesus left earth and went to heaven approximately 2000 years ago (Acts 1:9), but will come back again one day. Then Jesus will rule on Earth as king for 1000 years, when nature will be partially restored to what it was in the Garden of Eden, and there will finally be world peace. There are many prophecies in the Bible about Jesus' return, and many scholars believe that Jesus will be coming back very soon - perhaps in the next few years.
It is also important to note that Christianity is an extension of Judaism. The Bible contains the Old Testament (Genesis to Zechariah), which is all the old Jewish history books, religious laws, and such. However, the New Testament contains documentaries of Jesus' life and teachings, and also what Jesus' followers taught to the early Churches on how to live and follow God correctly. While Christians do still use the Old Testament, it is primarily a history book, and the old Jewish laws no longer apply to Christians. But it is still useful to learn from the stories and descriptions of how God helped the early Jews learn to follow God.
So how does this affect me?
So how will all this information affect you personally? If you believe what you have read above - that God did create the world, and Jesus did come to pay for our sins, then you may want to consider learning more about God and Jesus and how God wants you to follow him. You can do this by reading the Bible, reading what other Christians have written about Jesus and the Bible, and find a good Church to attend. A good Bible translation for beginners is the New International Version (NIV), which you can find at most major bookstores.
If you want to accept Jesus' payment for your sins right now, you can pray a simple prayer. Prayer is just talking to God/Jesus - you can do it out loud, or just think it in your head. You can say something like "Jesus, I realize that I've messed up and haven't acted how you wanted me to. I'm a sinner, and I deserve to go to Hell. But thank you so much for dying for me. I recognize that your death on the cross has paid for my sins, and that this is the only way to Heaven. Thanks so very much for your sacrifice and death, which I can never earn or repay. I pledge to follow you for the rest of my life - I want to act how you want me to act, learn more about you, and get to know and love you personally. I want you to be my Savior, and please teach me to love you and follow you. Amen".
If you have said this prayer sincerely, then you can be assured that God has wiped out your record of sins, and when you die you will go live with God forever. However, if you just pray this and walk away and never think about God again, then there is a risk you are not truly saved and you may not go to heaven. It is important to keep following God for the rest of your life, even though it will be difficult at times. But this life here is only a tiny moment in time compared to eternity, and it is well worth it to follow God.
Some notes on finding a good Church
Churches have people who can teach you more about God through the Sunday morning sermons, Bible studies, and other services they offer. You can also meet other Christians and get encouragement to keep following God. Personally, I would recommend a Protestant church - not Catholic. Catholics are mostly Christian, but add a lot of unnecessary traditions and rituals that are not taught in the Bible. It can be tricky nowadays to find a good Church - some are very traditional and some are more modern, but you can choose whatever you like. But be warned - some may not teach proper things about God or Jesus, and some are more like cults (i.e. Mormons and Jehovah's Witnesses), and it is important to avoid these cults.
If you are a new Christian, I would suggest you find a church that offers a program called "Alpha". Alpha is an introduction to Christianity where you can go once a week, have dinner or dessert, and learn about the basics of Christianity. There will be more experienced Christians that might be able to answer some of your questions, and you will also meet new Christians who are just starting out. Usually Churches which run Alpha programs are decent churches that will teach you correctly about Christianity, and won't confuse you with all sorts of other strange teachings.