Another theme in the prologue is John the Baptist, in ch.1 v.6-8, when the author clearly differentiates John and Jesus to show they are two different people, and that Jesus is the superior and they should not be confused, ‘He himself was not the light, but he came to testify to the light.’ The point that Jesus is the superior is reinforced later on in the prologue, in v. 15, when John says, ‘He who comes after me ranks ahead of me because he was before me.’
The third theme is that through faith and salvation, you can be saved and this is mentioned in ch.1 v.12-13, once you believed in Jesus, you became children of God and were saved.
Another theme of the prologue is incarnation, this is the idea of God and man becoming one in the being of Jesus, 'the word became flesh and made his dwelling among us,’ this is shown in ch1 v.14. The prologue states Jesus as God himself but in the form of flesh and life, therefore having a dualistic framework, the idea of having both a body and a soul. Jesus glory side of his being is shown by his ability to perform signs and heal people, including the dead, for example the rising of Lazarus in chapter 11. Glory of Jesus is seen particularly in the crucifixion where it was seen as a coronation rather than a time of suffering. However, Jesus’ humanity side is also shown by his emotions, when he wept, in that same chapter as Lazarus’ death (11.35) and when he is crucified and after his death, ‘one of the soldiers pierced his side with a spear and at once blood and water came out’, which shows that he had the body of a human.
One of the last themes seen in the Prologue is that of grace, this is undeserved love given freely with nothing expected back, which is often associated with God, and in this case is associated with God, Jesus and is shown in ch.1 v.16. So here Jesus embodies grace in the new covenant. Signifying salvation is through Jesus not the Jewish ritual of the 613 laws set in place by the Pharisee’s and the laws about circumcision.
The final idea within the prologue, is the law to love, in ch.1 v.17 and mentioned to precede the actual teaching later on in the gospel in ch.13 v.34 when Jesus said, ‘I give you another commandment, that you love one another. Just as I have loved you, you should love one another.’
Within the prologue there is a strong focus on the idea of logos, or the word, which doesn't appear elsewhere in John's gospel. The idea of logos was used as a title for Jesus, the author uses the term to emphasise Jesus' divine relationship. The idea can also be used because during the time when the gospel was written, the name of God was thought of to be wrong, as it was too holy to be written, so the title logos could have been used to in its place. Jesus’ divinity would also be easily understood by Jews reading the gospel as they would immediately make the connection that the gospel was about God. As the term logos is not explained in the prologue, the author assumes the audience will understand what he means. Guthrie says that ‘to the Greeks, logos would mean the rational principle governing the universe and to the Jews, logos would mean the pre-existent wisdom of God.’ This idea of universalism was also a way of drawing the Greek and Hellenistic readers to the gospel as the logos would have been a term they would have understood. ‘Logos was seen as the constant force in a world full of change.’ The title logos was also used as it also meant wisdom, this is important because in the inter-testamental books, these were the books that were written closest to the time period of the fourth gospel and people would understand immediately that Jesus was being talked about.
The word logos has substantial meaning behind it attributed from the Old Testament. God’s creative power is linked to the word of God, ‘Let there be light and there was light.’
From this it would appear that the Gospel is the key which unlocks the meaning of the fourth Gospel, but there are other theories that could contradict this point. For example Robinson claims that the prologue is a later addition to the gospel and was put in to bring things to a conclusion, similar to chapter 21. This idea could refute the gospel as the key to understanding the Gospel, because it merely prepares the reader for the ideas to come and doesn't present the ideas themselves in much detail. Rather than being a summary of the Gospel and its teachings is more of a contents list. Therefore, this idea would deny the claim that "The prologue is the key which unlocks the meaning of the fourth gospel", and could potentially mean it is to some extent pointless as it adds no new ideas to the gospel. But it could be possible to argue it does add a new idea, which is also very important, the idea of pre existence, with the logos. This is a very important idea that shows Jesus' divinity and presence with God from the very beginning, from the creation. Similarly it shows Jesus as the word, which isn't discussed anywhere else in the Gospel, and is also a key idea as it causes many ideas about the nature of Jesus and his importance, and relationship with God and mankind to come about.