Christians believe what is taught in the Bible.  Within its pages, there are basic doctrines that all Christians must believe and then there are teachings on which Christians can have different opinions.  I’ll explain what the basics of the Christian faith are using scripture.  Before you continue, let me say that the basic Christian beliefs are stated within the Bible as being essential.  In other words, there are warnings for denying them.  But, in the nonessentials of the Christian faith, there are no warnings. There is the freedom to believe differently.

The basic Christian beliefs

1. Monotheism – There is only one God in all existence
2. The Trinity – one God in three persons
3. Jesus – God in flesh
4. Jesus – died on the cross for our sins
5. Jesus – rose from the dead physically
6. Salvation – by faith alone, in Christ alone
7. Christians should repent of their sins and be baptized

Christian beliefs in which Christians can differ in opinions

1. Worship on any day of the week
2. Modes of baptism:  sprinkling, pouring, or immersion
3. Styles of worship: hymns, spiritual songs, different instruments

1) Monotheism – one God in all existence

The Bible teaches that there is only one God in all existence in all places at all times. A true Christian must believe that there is only one God and that we cannot serve a false God; otherwise, God will punish us (Exodus 20:3-5). This means that true Christians deny that other gods exist or will exist.

• Exodus 20:3–5, “You shall have no other gods before Me. 4 “You shall not make for yourself an idol, or any likeness of what is in heaven above or on the earth beneath or in the water under the earth. 5 “You shall not worship them or serve them; for I, the LORD your God, am a jealous God, visiting the iniquity of the fathers on the children, on the third and the fourth generations of those who hate Me,”
• Isaiah 44:6, “Thus says the LORD, the King of Israel and his Redeemer, the LORD of hosts: ‘I am the first and I am the last, And there is no God besides Me.”
• Isaiah 44:8, “Do not tremble and do not be afraid; Have I not long since announced it to you and declared it? And you are My witnesses. Is there any God besides Me, Or is there any other Rock? I know of none.’ ””
• Isaiah 45:5, “I am the LORD, and there is no other; Besides Me there is no God…”

2) The Trinity – one God in three persons

The Bible teaches that God exists as three coeternal, co-powerful, distinct persons: the Father, the Son, and the Holy Spirit. Yet, there is only one God, not three gods. When Christians speak of “persons” they do not mean what you and I might normally think of as a person. I am a person, and you are a person and are separate individuals. The Trinity is not separate individuals. Instead, the word ‘persons’ has a theological definition. A person is self-aware, aware of others, speaks, has a will, can love, hate, reason, etc. We find in Scripture that the Father, the Son, and the Holy Spirit each exhibit these attributes. Yet, each speaks about the other persons. Therefore, we say that God is a Trinity of persons.

THE TRINITY
	FATHER	SON	HOLY SPIRIT
Called God	Phil. 1:2	John 1:1,14; Col. 2:9	Acts 5:3-4
Everywhere	1 Kings 8:27	Matt. 28:20	Psalm 139:7-10
All-knowing	1 John 3:20	John 16:30; 21:17	1 Cor. 2:10-11
A Will	Luke 22:42	Luke 22:42	1 Cor. 12:11
Speaks	Matt. 3:17; Luke 9:25	Luke 5:20; 7:48	Acts 8:29; 11:12; 13:2
Love	John 3:16	Eph. 5:25	Rom. 15:30

Think of the Trinity by comparing it to time. Time is one thing, yet with three so-to-speak, parts: past, present, future.¹The word ‘parts’ is not the best theological word to use, since it implies that God can be divided. He cannot. Nevertheless, since this is a very introductory level article on the Trinity, it will suffice for now. For more information on the Trinity please see the articles  What is the Trinity? and The Trinity Chart  Each of those ‘parts’ of time all have the same nature: time. Yet, they are subtly different. The past has already happened, the present is happening now, but the future has not yet happened. This may not be the best analogy, but it is meant to convey the idea of how one thing can exist in three parts.

So, the Trinity is how the Bible reveals God.  He is one being who exists as three ‘theological’ persons:  the Father, the Son, and the Holy Spirit.  However, the doctrine of the Trinity is not revealed in a single Scripture nor does it contain a warning. But, it is derived from the whole of Scripture and since we are told to worship the true God and only him (Exodus 20:3-5), then the Trinity is an essential doctrine of the Christian faith.

3) Jesus – God in flesh

According to the Bible, Jesus is both divine and human. He is both God and man. The fancy theological term for this is called the hypostatic union. It simply means that in the one person of Christ are two distinct natures: divine and human. Yet, we see Jesus as a single individual.  Here are some of the Bible verses used to support this teaching.

• John 1:1, “in the beginning was the Word and the Word was with God and the Word was God.
• John 1:14, “and the Word became flesh and dwelt among us…”
• John 8:24, “unless you believe that I am, you will die in your sins.”
• John 8:58, “before Abraham was, I am.”
• Exodus 3:14, “God said to Moses, “I AM WHO I AM”; and He said, “Thus you shall say to the sons of Israel, ‘I AM has sent me to you.’”
• Col. 2:9, “for in him dwells all the fullness of deity in bodily form.”
• Heb. 1:8, “But of the Son he [The Father] says, ‘Your throne, O God, is forever and ever.'”

Noticed that Jesus said in John 8:24, “unless you believe that I am, you will die in your sins.” This means that you must believe he is God in flesh since he clients the same title of God Almighty appeared to Moses at the burning bush.

Articles related to this topic are Is Jesus God?, Jesus is God, Jesus’ Two Natures: God and Man, and Does the Bible ever refer to Jesus as God?

4) Jesus – died on the cross for our sins

Perhaps one of the most commonly understood things about Jesus is that he died on the cross. But what a lot of people don’t realize is that when it says he “died for our sins,” it means is that he bore our sins in his body on the cross (1 Pet. 2:24). Think of sin as breaking the law of God (1 John 3:4). But, laws have punishments. Otherwise, they’re not laws. They would be slogans. So, since sin is breaking the law of God, it is a legal (law) debt. If we break the law in society, there is a penalty. Let’s say that I violate the law by speeding, and I get a ticket. My legal debt is a fine. Once I pay it, the penalty has been satisfied. Jesus, so to speak, paid our fine. Think of it this way. Sin is a legal debt, and legal debts can be transferred. If you and I go to a restaurant and you forget your wallet, I can pay the cost of your meal; I can take your debt. Likewise, the penalty of our sin against God is transferable, and it was transferred to Christ on the cross. That is what it means for Jesus to die for our sins.

1. 1 Peter 2:24, “and He Himself bore our sins in His body on the cross, so that we might die to sin and live to righteousness; for by His wounds you were healed.”
2. 1 John 3:4, “Everyone who practices sin also practices lawlessness; and sin is lawlessness.”

Without Jesus dying on the cross for our sins, we have no hope of being delivered from the righteous judgment of God against all who have sinned against him. It is only through him that we can be separate because the Bible says that Jesus is “the way, the truth, the life, and nobody comes to the father but through him,” (John 14:6).

5) Jesus – rose from the dead physically

The Bible teaches that Jesus rose from the dead in the same body he died in, though it was a glorified body. Jesus prophesied his own resurrection in John 2:19-21. After His resurrection, He appeared to Thomas and told him to put his hand into His side and his finger into His hand (John 20:27). This demonstrates that Jesus had risen from the dead in the same body he died in because it retained the crucifixion wounds. Furthermore, 1 Cor. 15:42-44 is where Paul the apostle tells us that there will be a physical resurrection. The body is “sown in dishonor and raised in glory,” (1 Cor. 15:43). This is what we call a glorified body, and Jesus is the first one to rise from the dead in a glorified body (Col. 1:18). Without his physical resurrection, Christianity is false (1 Cor. 15:14, 17). So, a true Christian cannot deny that Jesus rose from the dead physically.

• John 2:19-21, ” Jesus answered them, “Destroy this temple, and in three days I will raise it up.” 20 The Jews then said, “It took forty-six years to build this temple, and will You raise it up in three days?”
  21 But He was speaking of the temple of His body.”
• John 20:27, “Then He said to Thomas, “Reach here with your finger, and see My hands; and reach here your hand and put it into My side, and do not be unbelieving, but believing.”
• 1 Cor. 15:14, 17, ” and if Christ has not been raised, then our preaching is vain, your faith also is vain… 17 and if Christ has not been raised, your faith is worthless; you are still in your sins.”
• 1 Corinthians 15:42–44, “So also is the resurrection of the dead. It is sown a perishable body, it is raised an imperishable body; 43 it is sown in dishonor, it is raised in glory; it is sown in weakness, it is raised in power; 44 it is sown a natural body, it is raised a spiritual body. If there is a natural body, there is also a spiritual body.”
• Colossians 1:18, “He is also head of the body, the church; and He is the beginning, the firstborn from the dead, so that He Himself will come to have first place in everything.”

6) Salvation – by faith alone, in Christ alone

Salvation is being saved from the righteous judgment of God upon all those who have sinned against him. The only way to be saved from God’s judgment is by faith in what Christ did on the cross. Since Jesus is God in flesh (John 1:1, 14), He was able to keep the Law of God perfectly (1 Peter 2:24). In other words, Jesus never sinned. But, unfortunately, we have all sinned (Romans 3:23) and, since the Bible says the wages of sin is death (Romans 6:23) and separation from Him (Isaiah 59:2), then all of us who have sinned will face the judgment of God. But, we want to be saved from that judgment. Again, this can only be accomplished by putting our faith in Christ.

When we put our faith in Christ alone, we are saved by faith alone in Him. This is because the Bible clearly tells us that no one can be justified (made right before God) by the works of the Law (Romans 3:28). In fact, the Bible tells us that though the one who does not work but believes, his faith is reckoned as righteousness (Romans 4:5).

When we put our faith in Christ alone, we are saved by faith alone in Him. This is because the Bible clearly tells us that no one can be justified (made right before God) by the works of the Law (Romans 3:28). In fact, the Bible tells us that the one who does not work but believes, his faith is reckoned as righteousness (Romans 4:5).

We know this is an essential doctrine of the Christian faith because of what Paul the apostle tells us in Galatians 5:1-4. In those verses, Paul is dealing with what was called the Judaizers. They were Jews who were requiring that the Gentiles, who converted to Christ and get circumcised in order to be saved. Circumcision was part of the Old Testament Law requirements. But Paul said that anyone who seeks to be justified (made right according to the law) by circumcision, or anything else in the Law, is not saved.  This would be because it would not be by faith alone in Christ alone that we are saved. Instead, it would be by faith in our own ability and that is impossible because we are simply not good enough to satisfy a holy and infinite God.

• Isaiah 59:2, “But your iniquities have made a separation between you and your God, and your sins have hidden His face from you so that He does not hear.”
• Isaiah 64:6, “For all of us have become like one who is unclean, and all our righteous deeds are like a filthy garment; and all of us wither like a leaf, and our iniquities, like the wind, take us away.”
• Romans 3:28, “For we maintain that a man is justified by faith apart from works of the Law.”
• Romans 4:5, “But to the one who does not work, but believes in Him who justifies the ungodly, his faith is credited as righteousness,”
• Rom. 6:23, “For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.”
• Galatians 5:3–4, “And I testify again to every man who receives circumcision, that he is under obligation to keep the whole Law. 4 You have been severed from Christ, you who are seeking to be justified by law; you have fallen from grace.”
• 1 Pet. 2:243

So another essential doctrine of Christianity is salvation is by faith alone in Christ alone.

7) Christians should repent of their sins and be baptized

Repentance means to change one’s mind, to change your attitude towards something. It means to turn away from it. All Christians who trust in Christ must turn from their sins. If they don’t turn from their sins, then they are not saved, (1 John 2:4).

Baptism is a ceremony that symbolizes the death burial and resurrection of Christ (Rom. 6:3-4) and how a Christian, in his baptism, is identifying with Christ’s death, burial, and resurrection. It is an outward sign that a person has trusted in Christ and seeks to die to the world and live for Jesus.

However, neither our repentance of sin nor baptism is what saves anybody. These are necessary results of those who truly trust in Christ. We cannot say that someone is a true Christian who continues to live in sin and yet refuses to be baptized. So, this is another of the basic doctrines that reveal what Christians believe.

• 1 John 2:4, “The one who says, “I have come to know Him,” and does not keep His commandments, is a liar, and the truth is not in him;”
• Romans 6:3–4, “Or do you not know that all of us who have been baptized into Christ Jesus have been baptized into His death? 4 Therefore we have been buried with Him through baptism into death, so that as Christ was raised from the dead through the glory of the Father, so we too might walk in newness of life.”

Christian beliefs in which Christians can differ in opinions

Though there are essential doctrines of the Christian faith that are listed above, there are other things in the Bible which Christians can differ upon and still be true Christians. This is because the Bible does not explicitly state that these things are essential to the Christian faith. For example, we can worship on any day of the week as is stated in Romans 14:5.  Also, baptism can be performed in three different ways, by sprinkling, by pouring, and by immersion, then there are different styles of worship. Some people prefer to use old-fashioned hymns while others prefer more contemporary worship songs. There are churches that use musical instruments during worship and others do not.

In Christianity, there is a topic called eschatology. This means the study of future things. Within eschatology, there are different opinions about what will happen before Jesus comes back. Some topics are debated within Christian circles including the millennium, the tribulation, and the rapture. These are debatable topics on when they will occur. But nothing in Scripture says that we have to believe a certain thing in order to be a true Christian.

• Romans 14:5, “One person regards one day above another, another regards every day alike. Each person must be fully convinced in his own mind.”

Conclusion: Essential and nonessential Christian beliefs

So, there are essentials of the Christian faith and then there are nonessentials to the Christian faith. The essentials are what makes Christianity Christian. And that, listed above, are the basics of the Christian faith.