Below are some excerpts from Anders Breivik’s Manifesto entitled "2083 - A European Declaration of Independence." (1500 page web document)
"A majority of so called agnostics and atheists in Europe are cultural conservative Christians without even knowing it," he wrote.
"If you have a personal relationship with Jesus Christ and God then you are a religious Christian. Myself and many more like me do not necessarily have a personal relationship with Jesus Christ and God. We do however believe in Christianity as a cultural, social, identity and moral platform. This makes us Christian," he wrote.
What is a Christian? Many think they are Christians because they claim to believe in the cultural Jesus. But, believing in Jesus often means nothing, or anything you want it to mean, particularly here in the case of Anders Breivik. But it doesn't change the true meaning of what it means to be a follower of Christ. So, what does it mean to be a Christian?
First of all, to be a Christian, you must first know who Jesus Christ is. Biblically, He is God in flesh, second person of the Trinity (John 1:1,14; Col. 2:9). He is the great "I AM" (Exodus 3:14; John 8:58). He is the savior who was born of a virgin (Isaiah 7:14), who died, was buried, and rose from the dead (1 Cor. 15:1-4), physically (John 2:19-21). He alone is the way, the truth, and the life (John 14:6). Only by the name of Jesus may a person be saved (Acts 4:12) and all who do not trust in Him alone for the forgiveness of their sins will be judged (Matt. 25:41) accordingly. Jesus is both God and man (Col. 2:9; 1 Tim. 2:5; Phil. 2:5-8). He is our eternal intercessor (Heb. 7:25) who mediates our salvation to the Father (1 Tim. 2:5). He is the creator of all things (Col. 1:16-17; Isaiah 44:24). He is Lord! To Him be the glory!
Once you know who Jesus is, you must trust Him to forgive you of your sins. Ask Him to forgive you. He will. Then, once you are saved, you are a Christian. It means you have found the true Savior, not a false one of the cults. It means you have been saved by God's grace, through faith (Eph. 2:8) and are now seeking to please Him in your life by following His commands (1 John 2:4). Such obedience does not save you nor contribute to your salvation. This obedience is motivated by love and thankfulness and is a response of being saved.
So, being a Christian means knowing the true Christ and following Him in truth.