What is Christianity?
Christianity is a worldview – a framework of ideas and beliefs through which an individual interprets the world and interacts with it. The Bible informs the Christian, a follower of Jesus (an adherent to Christianity), as to the particulars of that worldview.
Those particulars can be summed up in one, crucial, all-important word – the gospel. Gospel simply means “good news.” Mark Dever and Paul Alexander, in their book The Deliberate Church (Crossway Books, 2005, 221 pages), offers this one paragraph summary defining the gospel, and hence, Christianity and what it fundamentally proclaims as the truth about the world and how we should interact with it.
This Gospel, then, is that God is our holy Creator and righteous Judge. He created us to glorify Him and enjoy Him forever, but we have all sinned, both in Adam as our representative head, and in our own individual actions.1 We therefore deserve death—spiritual separation from God in hell2—and are in fact already spiritually stillborn, helpless in our sins3 and in need of God to impart spiritual life to us.4 [Given our desperate condition what follows is why the Gospel is supremely good news] But God sent His Son Jesus Christ , fully God and fully man,5 to die the death that we deserved, and he raised Him up for our justification, proving that He was God’s Son.6 If we would have Christ’s perfect righteousness credited to us, and the penalty for our sins accounted to Him, we must repent of our sins and believe in Jesus Christ for salvation.7 (p. 28)
This the essence of Christianity, the glorious gospel of the blessed God.8