Some of the major theological themes found in the Fourth Gospel are:

• Purification
• Logos
• Paraclete
• Marriage
• Water
• Lamb of God
• Wine
• Jewish Festivals

The theme of Purification recurs in John's Gospel on many occasions. This theme has many links with the theology of the Old Testament and with the ritual of the Jewish people. It is often difficult for the modern mind to grasp the full extent of this important concept. Whenever the people of Israel ritualized the act of purification it is representative of being in the presence of the Almighty. We tend to think of purification ritual as something which cleans what is unclean, but this is not the theological significance of the ritual. This might best be illustrated by an example drawn from real life. Following childbirth a woman was required to offer a holocaust and a sin offering (Lev 12:1-8). We must remember that for the Jewish people marriage is sacred and childbirth is a blessing. So, a new mother is not in a state of sin. But she had come into contact with the creative power of God and consequently had to be 'purified' in the ritual sense, before returning to her normal activities.

The concept of purification can be seen, for example, on two very different occasions in John 2:  the ritual jars at the wedding of Cana and the act of cleansing the Temple.

The Cleansing of the Temple

In the current context one cannot afford to ignore the occurrence of two events side-by-side in Chapter 2. The first half of the chapter deals with the Marriage at Cana while the second half describes the cleansing of the Temple in Jerusalem by Jesus. One way in which these two incidents are linked lies in the word shmeiwn which means 'sign'.   In 2:11 John describes the Cana miracle as the archn shmeiwn, the beginning of signs. Then, in 2:18 he is challenged by the Jews to show a sign to legitimize his action in cleansing the Temple and his claim that he would raise it up in three days. This is certainly a reference to his death and resurrection - arguably the last and greatest of his signs. Hence the Cana miracle and the cleansing of the Temple are linked by the fact that the first was the beginning of Jesus' signs and the second looks forward to the last and greatest of the signs.

There is an explicit reference in the narrative of the cleansing of the Temple to Psalm 69:9 - 'Zeal for your house will consume me'. This could be seen as a device for demonstrating to the reader that the disciples realized that the words of this Psalm emanate from a pre-existent Christ. It is a Psalm of the righteous sufferer, the meaning of which is only clear in the context of the Christ revelation - the one to whom it was clearly pointing. There is, furthermore, an indication that we have deepened our understanding from the Christ in John 1:51 who represents the place of God's presence to Christ as the house of God.

It would appear from Matthew's gospel that the early Christian community made a connection between Psalm 8 and the incident of the cleansing of the Temple. In rabinnic tradition Psalm 8 is associated with Moses: when Moses went up to heaven to receive the Torah the angels protested saying 'What is man that you are mindful of him, and the son of man that you visit him?' Thus John might well be inferring a similar situation by using the 'sheep and cattle' image (Jn 2:15b) i.e. countering the claims made on behalf of Moses by the synagogue with claims that Christians are making on behalf of Christ. Unlike the synoptic writers, John does not quote Isaiah 56:7 and Jer 7:11. He seems to want to divert our attention from the historical Temple and focus it on the future spiritual Temple to be found in Christ. Many scholars see a link with Zech 14:21 'And there shall no longer be a trader in the house of the Lord of hosts on that day'. If this is the case then there could be an underlining of the eschatological significance of the cleansing.

The other more common conceptualization of purification aims at removing a legal obstacle to contact with the divine. By undergoing ritual purification the individual is prepared for the encounter with God. It is easy to see how this interpretation is in keeping with the over-riding purpose of John's Gospel - the revelation of the Glory of God and the preparation of all peoples to meet with the divine.
 

Jesus washes the feet of his disciples (Jn13:5-12)

The foot-washing rite points forward to the actual cleansing work of Christ on the cross. John probably sees in this incident an echo of Psalm 109:4-6 wherein we read:

"In return for my love they accuse me
even while I make prayer for them.
So they reward me evil for good,
and hatred for my love.
They say, "Appoint a wicked man against him;
Let an accuser stand on his right."

In the LXX the word for 'accuser' is diabolos, and it is very likely that John would understand this as a reference to the devil. Thus the concept of purification has both ritualistic and soteriological overtones.  Jesus is the one who takes away the sins of the world, the Lamb of God.  Many of the theological themes of the Fourth Gospel point to this purifying and salvific role of Jesus.

In the Old Testament the revelation of God was through the word.  For the Hebrews the word continues to exist. After it is spoken, it cannot be taken back.  A blessing continues to bless and a curse continues to curse after they have been uttered.  Thus, in Old Testament terms, the Logos is the Law.  The Logos is the eternal truth (the alhqeia) which has been revealed by God.

The concept of Logos is introduced in the Prologue.  Scholars have discovered that this part of the text derives from a pre-Christian hymn, composed by Jewish poets in praise of the Torah.  They said that the Torah was the Law, wisdom, word.  They said that the Torah was with God from the beginning and was the instrument by which God made the world.  The Torah lay in God's bosom from the beginning.  It was full of grace and truth.  John evidently takes this hymn in praise of the Torah and transfers the honor from the Law to Christ.  Jesus supersedes the Torah.

There are five Paraclete sayings in the Gospel of John.  They all occur within the farewell discourses (14:16; 14:26; 15:26; 16:7-11; 12-15)

Jn 14:16 'And I will ask the Father, and he will give you another Advocate (paraklhton), to be with you forever.'
This seems to be reminiscent of Job 16:19-21where it is written:

"Even now, in fact, my witness is in heaven,
and he that vouches for me is on high.
My friends scorn me;
My eye pours out tears to God,
That he would maintain the right of a mortal with God,
As one does for a neighbor.
For when a few years have come,
I shall go the way from which I shall not return."

Another major Old Testament source for the pneumatology of John is Wisdom.  We read in Wis 1:4-6:

"Wisdom will not enter a deceitful soul, or dwell in a body enslaved to sin.  For a holy and disciplined Spirit will flee from deceit.... For Wisdom is a kindly Spirit, but will not free blasphemers from the guilt of their words; because God is a witness of their innermost feelings, a true observer of their hearts."

The theme of marriage and weddings occurs several times in the Fourth Gospel.  In the second chapter Jesus gives the first of the signs worked by Jesus in the context of a marriage feast, at Cana in Galilee.

The Marriage at Cana (Jn 2:1-12)
On the face of it this is a naïve tale about a marvel at a village wedding.  There is realism, an eye for character and for seemingly trivial detail.  And yet, we are told that 'Jesus did this as the beginning of his signs, and so manifested his glory'.  The last words of the Cana pericope recall the Prologue 'The word became flesh and pitched his tent among us, and we beheld his glory'.  As is so often the case in the Fourth Gospel the true meaning of this story lies deeper within the text.

There are no clear Old Testament links within this part of the text.  However, perhaps there is a clue in the first verse .... "On the third day"...  Why does John choose to give us this information?  Could it be a link with the day of resurrection?  Certainly this theme is carried on in the second part of Chapter Two - "Destroy this temple, and in three days I will raise it up" (2:19).  It was also on the third day that the people of Israel arrived at Sinai and promised to obey Yahweh - just as the servants in 2:5 promise to obey Jesus.  On Sinai the people behold the glory of God - and here Jesus' glory is revealed to his disciples (2:11).

The wedding context may be significant - In Hos2:21f, Jer 2:2 and Is 54:5f, for example, we see the OT figure of Israel as the spouse of Yahweh.  While Israel is sometimes deemed to be unfaithful, Yahweh is always faithful.  This figure developed in Judaism and even saw in a wedding feast the symbol for the Messianic age. Thus, this text could be construed as a revelation by Jesus of the Messianic age - a clear sign that HE is the Messiah who was promised.

The narrative can also be interpreted in a Eucharistic vein - reminiscent of Melchizedek (Gen 14:18) who offered bread and wine to Yahweh.  Furthermore, John locates this event near the feast of Passover (Jn 2:13) - as indeed he also does the multiplication of the loaves and fishes (Jn 6:4f) - perhaps indicating that the Eucharistic sacrifice is the Christian Passover.
 

John clearly sets the scene for interpretation by referring directly to the Genesis narrative:
John 4:5-6 ". near the plot of ground that Jacob had given his son Joseph. Jacob's well was there, and Jesus, tired out by his journey, was sitting by the well. It was about noon."  This draws our attention to:

Genesis 33:19 - where Jacob buys a piece of land at Shechem
Genesis 48:22 - where Jacob on his death bed gives to Joseph a mountain slope which he took from the Amorites
Joshua 24:32 - remembering how the descendants of Joseph lifted his bones from Egypt and carried them for burial at Shechem

Olsson sees a marked parallel between the narrative in chapter 4 and the account of Moses at the well of Midian found in Exodus 2:15-21. This is especially in the form in which it is reproduced by Josephus - i.e. it was noon; Moses was tired; women came to the well; women came to the well; Moses had no food.

So now the incarnate Logos is reproducing in the new age the experience of Moses under the old dispensation. There might also be a link with Numbers 21:16-18:

'From there they continued on to Beer; that is the well of which the Lord said to Moses, "Gather the people together, and I will give them water." Then Israel sang this song: "Spring up, O well! - Sing to it! - the well that the leaders sank, that the nobles of the people dug, with the scepter, with the staff."'

Indeed, such commentators as C.H. Dodd, using the above interpretation, explicitly state that the water from the well (the Torah) is dead, in comparison to the life-giving and living water that Jesus provides.  Dodd looks at other texts:
            Zech 14:8 "On that day living waters shall flow out from Jerusalem, half of them to the eastern sea and half of them to the western sea."
            Ezek 47:1 - the water flows eastwards from the threshold of the Temple to fertilize the desert.

Both of the above texts could be interpreted as representing a foreshadowing of the end of the Jewish-Samaritan schism.  This is further supported by the text from Isaiah 11:13 (where Ephraim might, for John, represent the Samaritans):-

"The jealousy of Ephraim shall depart,
the hostility of Judah shall be cut off:
Ephraim shall not be jealous of Judah,
and Judah shall not be hostile towards Ephraim."

As an aside, several scholars point out that meetings at the well in the Old Testament sometimes led to marriage.   Some examples of this are: -

Abraham's servant in Genesis 24 meets Rebekah at a well and arranges a marriage between her and Isaac.
Jacob first met the women he was to marry (Rachel and Leah) at a well - Gen 29
Moses met Zipporah at a well - Exodus 2
Also, in the Song of Solomon (4:15) the bride is described as a 'well of living water'.

'The scepter shall not depart from Judah,
Nor the ruler's staff from between his feet,
Until he comes to whom it belongs;
And to him shall be the obedience of the peoples'.

In Proverbs 18:4 we read: 'The words of the mouth are deep waters; The fountain of wisdom is a gushing stream'.
This verse as translated from the LXX (above) exactly expresses what John is intending to convey. If the Logos, the Risen Christ, dwells in a person's heart, they will become a gushing stream.

Isaiah 12:3 'With joy you will draw water from the wells of salvation' - here the Prophet urges Israel to make God's deeds known among the nations. This ties in with the universalistic tone of John 4:21-25 where it is implied that the worship of God will not be confined to Mount Zion or Mount Gerizim.

To begin with, it is necessary to note that this is one of the most frequently alluded-to themes in the Fourth Gospel, occurring as it does, some 25 times.  In many parts of the Old Testament the manna and the water from the rock are often linked together - e.g. in Nehemiah 9:15 we read, 'For their hunger you gave them bread from heaven, and for their thirst you brought water for them out of the rock...'  So, in John, we should not be surprised to read of the Bread of Life in Chapter 6 followed by the Living Water in Chapter 7.

John gives us a time reference for this discourse of Jesus.  The Feast of Tabernacles (or Booths) is a commemoration of the forty years in the wilderness.  It was practice on this Feast to draw water from the Pool of Siloam and pour it into a silver bowl at the altar.  It is difficult to determine the exact origins of the accompanying Scripture citation "Out of the believer's heart will flow rivers of living water". Some claim it comes from Isaiah 44:2-3, while others maintain that it is from the prophet Zechariah.  This latter claim accrues more credibility whenever one realizes that the text read on the Festival of Tabernacles comes from Zechariah 14:8.

"On that day living waters shall flow out from Jerusalem half of them to the eastern sea, and half to the western sea..."

The theme of water is also taken up in the account of the dialogue between Jesus and The Samaritan Woman at the Well (Jn 4:1-26)