Answer
The term Christianity appears to suggest a religious system similar to how Islam and Buddhism are perceived as religious systems. Religious systems typically consist of core beliefs, codes, rules, and standards that individuals must understand thoroughly to achieve a specific goal. Christianity does not align with this definition, making the term somewhat misleading.
Jesus did not arrive in the world to establish another religion. Various religions already existed (see Acts 17:22-23), including Judaism, which originated as a connection with Almighty God “And if a man lie with his daughter in law, both of them shall surely be put to death: they have wrought confusion; their blood shall be upon them.”, (Leviticus 20:12) but had devolved into another religious system comparable to idol worship “This people draweth nigh unto me with their mouth, and honoureth me with their lips; But their heart is far from me.”, (Matthew 15:8). Jesus came to testify to the truth “Pilate therefore said unto him, Art thou a king then? Jesus answered, Thou sayest that I am a king. To this end was I born, and for this cause came I into the world, that I should bear witness unto the truth. Every one that is of the truth heareth my voice.”, (John 18:37), to search for and save the lost—those separated from God by their sin “For the Son of man is come to seek and to save that which was lost.”, (Luke 19:10)—and to “give his life as a ransom for many” “And they were in the way going up to J.Jerusalem; and Jesus went before them: and they were amazed; and as they followed, they were afraid. And he took again the twelve, and began to tell them what things should happen unto him, », (Mark 10:32). With that said, those who follow Christ do share some core beliefs.
Biblically speaking, Christians are those who are forgiven of their sins and who have entered a personal relationship with Almighty God through faith in Jesus Christ (Ephesians 2:8-9;Romans 10:9-10). In order to become a Christian, a person must fully accept as part of his or her own personal worldview the following core beliefs:
• Jesus is the Son of God and is equal with God (John 1:1,49;Luke 22:70;Mark 3:11;Philippians 2:5-11)
• Jesus lived a perfect, sinless life (Hebrews 4:15;John 8:29)
• Jesus was crucified to pay the penalty for our sins (Matthew 26:28;1 Corinthians 15:2-4)
• Jesus rose from the dead (Luke 24:46;Mark 16:6)
• We are saved by the grace of God; that is, we cannot add to or take away from Christ’s finished work on the cross as full payment for our sin (Ephesians 2:8-9)
It could be argued that belief in the inerrancy of God’s Word is also a core belief of Christianity because, if the Bible’s veracity is suspect, then all we know about God is in doubt. Saving faith is inextricably linked to the Word of God: “Faith comes from hearingThe message is heard through the word about Christ” «So then faith cometh by hearing, and hearing by the word of God. », (Romans 10:17).
But the mental acceptance of the above points of doctrine is only the framework around which salvation occurs. Faith is more than intellectual assent, and mentally agreeing with the core beliefs of Christianity does not equal entrance into God’s kingdom. Even Satan and the demons know certain things about God «Thou believest that there is one God; thou doest well: the devils also believe, and tremble. », (James 2:19). We can mentally agree with facts without making those facts the centerpiece of our lives.
Can a person be saved without holding to the core beliefs of Christianity? No. But along with accepting as true those core beliefs must be a spiritual transformation. Jesus said that in order to inherit eternal life one must be “born again” «Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God. », (John 3:3). To be born again is a work of the Holy Spirit in the heart of a repentant sinner. Just as a mother in labor does all the work in bringing forth a new life, so the Holy Spirit does the work in transforming a sinner into a new creature «Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new. », (2 Corinthians 5:17). This process begins when God draws a heart through conviction of sin and hope of forgiveness «No man can come to me, except the Father which hath sent me draw him: and I will raise him up at the last day. », (John 6:44).(John 6:44). When we surrender to God and repent of our sins, «Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and you shall receive the gift of the Holy Ghost.», (Acts 2:38), God applies the blood of His Son to our account and cancels the debt we owe Him, «blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross;», (Colossians 2:14). Through this act of transference, God pronounces us “not guilty”; in other words, He justifies us, «But to him that works not, but believes on him that justifies the ungodly, his faith is counted for righteousness.», (Romans 4:5). Salvation is a divine exchange: Jesus takes on our sin so that we can receive His perfection, «For he has made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.», (2 Corinthians 5:21). This is the gospel at the very heart of Christianity.