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Understanding Key Christian Concepts

Translating Christianese

When you give your life to Jesus and become a Christian, it’s easy to become bewildered by what some people jokingly call “Christianese”. There are a lot of words that are commonly heard in Christian circles (or key Christian concepts), but unless someone explains them to you, it’s hard to understand what’s being said or meant or implied. This section aims to explain some of the common “Christianese” key Christian concepts that form the building blocks of the Christian faith. 


Repentance means being serious about turning away from the “old life” of sin and putting your trust in God’s saving grace through faith in Jesus.

There’s a big difference between true repentance and just saying sorry because you know that saying sorry will get you off the hook. We’ve all done it. We’ve done something wrong, and we’ve had to be ‘disciplined.’ Whatever the punishment, we learn young that if we say sorry quickly enough, then the punishment won’t be so severe – but that doesn’t necessarily mean that we’re really sorry (or that we won’t do exactly the same thing again!)

Repentance isn’t just about saying sorry. You have to mean it. It’s about change, making an effort to do things differently. When we become Christians, the Holy Spirit will help us to turn away from sin completely.


Sin is a word that gets spoken about a lot, but people don’t always understand what it means. Basically, sin is:

  • Anything that is bad or wrong
  • Anything that hurts you or someone else
  • Anything against the law
  • Anything against your conscience
  • Anything the Bible tells us not to do

Sin is one of the biggest weapons the devil can use against us. The things that tempt us that we know are wrong are the enemy’s way of trying to lead us astray and lead us away from Jesus. Some people think that once they’ve sinned, that’s it, they’ve lost their salvation, but that’s not the case. It’s just a matter of repenting of the sins we’ve committed when the devil has tempted us away from Jesus and accepting the forgiveness that Jesus extends to us because of our repentance.


Grace is another Christian word that gets used a lot without ever being properly explained. There are, in fact, lots of different ways of explaining the concept of grace. These are just some of them:

  • What we get when we are truly repentant
  • God’s unmerited favor
  • Something that we can’t earn – it’s a gift from God
  • Having the slate wiped clean so that our sins are forgiven
  • Getting the forgiveness we don’t deserve instead of the punishment we deserve!

We’ve even heard of grace being defined as God’s Riches AChrist’s Expense.


Turning to Christ is otherwise known as faith. In order to turn to Christ and develop faith, we need to know who He is and what He has done.

But simply knowing the facts about Jesus’ life, death and resurrection doesn’t give us faith. Non-believers can know the facts about Jesus without being saved. Neither is it enough to know the facts and agree that they are true.

Faith means knowing the facts about Jesus, agreeing that they are true, and then making a decision to depend on Jesus to save us. This means moving from being an observer who just knows the facts to being in a personal relationship with Jesus.

Wayne Grudem defines faith in a single sentence: “saving faith is trust in Jesus Christ as a living person for forgiveness of sins and eternal life with God.


According to the Bible, salvation happens when we repent and come to faith – so it is a matter of deciding to put your trust in Jesus to save you and deciding to forsake sin and live out the rest of your life in obedience to Jesus.

Some people have the wrong idea about salvation – they think that they can be saved just by having faith in Jesus Christ, but it’s not as simple as that. Salvation also requires repentance – you can’t be saved by faith alone, nor can you be saved by repentance alone. Salvation is a combination of the two, and one without the other just isn’t salvation!


Forgiveness is one of the things that is promised to believers in the gospel message of Jesus Christ. It is also one aspect of something called “justification.” Jesus promises that if we come to Him in faith and repent of our sins, we will be forgiven for our sins. In Acts 3:18, the Apostle Peter calls forgiveness the blotting out of our sins – it means that once we have genuinely repented and put our trust in Jesus, our sins will no longer be held against us.

There is another aspect to forgiveness, though – it is not just something we receive. We are obliged to extend it to other people who have hurt us. We are commanded to forgive others as we have been forgiven by God.

Old Testament

The whole Bible is made up of 66 books. The Old Testament is a collection of 39 books that were written before Jesus was sent to the earth to die for our sins. The Old Testament contains the story of creation and things like the stories of Abraham, Joseph, and the Exodus from Egypt. It contains the story of David and Goliath, Samson and Delilah, and Noah’s Ark. The Old Testament is the part of the Bible that the Jewish people believe in.

The Old Testament is made up of different types of books. The first five books are sometimes called the Pentateuch or the Torah. The Ten Commandments and other Jewish laws can be found there. Other types of books in the Old Testament include history books, such as 1 &2 Chronicles, poetry books, like the Psalms, and prophetic books, such as Jeremiah and Joel.

Some people ask why we need to read the Old Testament if it was written hundreds of years before Jesus was born, but Christians believe that the whole Bible was given to us as the Word of God, so it’s important to read both the Old and the New Testaments.

New Testament

The New Testament is the remaining 27 books that make up the whole Bible and comprises books that were written after the birth, death, and resurrection of Jesus Christ. The first four books of the New Testament are known as the gospels. The word ‘gospel’ means ‘good news,’ and these four books tell the good news about Jesus Christ.

The first three gospels, Matthew, Mark, and Luke, are very similar (and are known as the synoptic gospels) whilst the fourth, John, takes a slightly different approach to sharing the gospel of Jesus. The fifth book in the New Testament is called the book of Acts and tells of the Acts of the Apostles after Jesus was taken up to heaven following His resurrection. 

Revelation is the very last book in the Bible. It is often regarded as a prophetic book as it discusses what will come at the End of Days. In between Acts and Revelation are a series of letters, sometimes referred to as Epistles, that were written by the Apostles to different groups of Christians (such as the church at Ephesus) or to individuals (such as Timothy). These books tell us a lot about our faith and answer some questions about living Godly lives.


Put simply, justification is what happens when we are saved by our act of faith and repentance. By saying that we are justified, it means that God now sees us as forgiven of our sins and declares us to be righteous in his sight. We couldn’t possibly achieve justification by anything that we do, and in that sense, it is a gift of God’s grace that we have justification. We are justified by our faith in Jesus Christ, who took upon Himself our sin so that we could take upon ourselves His righteousness.

One very common Christian phrase is “justification by faith alone” – this just means that whilst we are called as Christians to do good works, we cannot achieve our justification through doing good things. Only our faith in Jesus can justify us.


Baptism, sometimes called water baptism to distinguish it from the Christening of babies, is a public declaration of faith. What happens is that a believer is immersed fully in water after declaring that they are turning away from their sins and choosing to follow Jesus. There is a symbolism to baptism, too. It represents the way that Jesus died and was resurrected. In baptism, we are dying to our old, sinful selves as we go under the water and being resurrected into a new life of Christ-likeness as we rise up from the water again.

Baptism can only be done once – the Bible tells us there is “one Lord, one faith, and one baptism” (Ephesians 4:5).

Baptism in the Holy Spirit

Baptism in the Holy Spirit is a very different thing from water baptism. For one thing, it doesn’t involve water! Baptism in the Holy Spirit is what happens when a believer, who is committed to a life of following Jesus, is filled with the Holy Spirit.

Often, when someone is filled with the Holy Spirit, they will start to be able to speak in another language – known as speaking in tongues. This is what happened on the Day of Pentecost, which you can read about in Acts 2.

However, speaking in tongues isn’t the only gift you can receive when you are filled with the Holy Spirit. There are other Spiritual Gifts. And unlike water baptism, being filled with the Holy Spirit isn’t a once-only event. People can be re-filled with the Holy Spirit many times, and indeed, we are told to seek to be filled with the Holy Spirit frequently.

Spiritual Gifts

There are several places in the New Testament where Spiritual Gifts are spoken of. Broadly speaking, a Spiritual Gift is any ability that is given to a believer by the Holy Spirit that is used for the benefit of the whole body of Christ (that is, the church as a whole). They are given to believers when they are filled with the Holy Spirit.

Some of the Spiritual Gifts mentioned in the Bible include:

  • healing
  • words of wisdom and words of knowledge
  • prophecy
  • miracles
  • speaking in tongues and interpreting tongues
  • teaching
  • encouraging others
  • showing mercy

The Fall

‘The Fall’ describes what happened in Genesis 3. Satan tempted Eve into eating fruit from the tree of knowledge of good and evil, which God had forbidden Adam and Eve to eat from. When Eve took the fruit and gave some to Adam, and they both ate the fruit, everything changed. The Bible tells us their eyes were opened to their nakedness and that they felt shame. Previously, they had felt no shame.

But it was more serious than that. It was at the moment when Eve agreed with satan and disobeyed God that sin entered into the world. Man gave up his right to have dominion over all the earth when he was led astray by Satan. God had given man dominion over the animals and land of the earth, and he just handed over that right to satan. Man fell from being rulers over all the earth to being subjects of satan, (otherwise known as the ‘prince of this world.’)

The Impact of the Fall

The Fall also changed man’s relationship with God. Before the Fall, Adam and Eve had had a very close, intimate relationship with God – the Bible tells us that God used to walk with man in the Garden of Eden – but once they ate from the tree of knowledge of good and evil, their relationship with God changed. They hid from God when He came to walk with them because they were ashamed of their nakedness. 

There was more to it than that, though. Sin entered the world when Adam and Eve disobeyed God. Man’s sinfulness separated them from God. That meant they couldn’t enjoy an intimate relationship with Him again – until Jesus died on the cross to pay the penalty for our sins and restore us to an intimate relationship with God.

The sin that entered into the world at the time of the Fall is what separates us from God, and until we have a personal relationship with Jesus as our Lord and Saviour, we remain under the effects of the Fall. We need Jesus to restore us to an intimate relationship with God again.

Got More ‘Christianese’ You Need Translating?

I’ve tried to cover the most common key Christian concepts in this guide, but if there are any key Christian concepts that you think we’ve missed and want translating from Christianese, visit our contact page to submit a request.