There is much speculation from scholars as to why John chose to include the signs, which are unique to the fourth gospel. Broadly speaking, there are two main views. The first is that the signs were intended purely to be accurate accounts of Jesus’ miracles, featuring historically and topographically factual details. The second, and perhaps more widely held, is that John had an evangelistic purpose in mind when he wrote the signs: he wanted to make his readers believe.
John chooses to use the word ‘semeia’, meaning ‘signs’, rather than the ‘dunameis’ (‘mighty act’, used in the synoptics) to denote the miracles that Jesus performs. Whereas ‘act’ is a word firmly rooted in a particular place and timeframe, the word ‘sign’ evokes the idea of the miracles pointing to something else, or foretelling a future event. It implies a greater role and purpose to Jesus’ miracles than the acts themselves, a divine scheme, thus helping the reader see the link between Jesus (who looks like an ordinary person) and the Father. John’s choice of words alone suggests he wanted the signs to be seen by the reader in a theological light, not an historical one. In fact, John explicitly says of the signs:
‘These are written that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in his name.’ (John 20:31)
Tasker mentions that some scholars in the past believed this statement to be a later addition to the gospel, by a later author or redactor. However, since there is no evidence for this, it is necessary to assume that the original author of John’s gospel wrote the statement themselves. For this reason, it cannot be denied that one of, if not the, main purpose of the signs is to fulfil an evangelistic role.
Some might argue that there are parts of the signs that seem to contradict this purpose. For example, neither the third or fourth sign ends with true faith from those involved. In the third sign, the Healing at the Pool, the crippled man does not embrace Christ’s teachings but instead goes straight to the Jewish authorities, and even tries to shift blame onto Jesus for disregarding the rules of the Sabbath. At the end of the fourth sign, the Feeding of the 5,000, the crowd tries to make Jesus king by force. They do not understand that, as Sanders and Mastin put it, ‘Jesus was a king, but…his kinship was not of this world’. Both signs three and four end in the same way: with Jesus quietly leaving the scene, because he has failed to inspire people to faith as he had hoped.
Although these signs do result in negative outcomes, they are quite possibly a tool John has deliberately employed to help his readers understand the nature of faith. By giving clear examples of people not recognising Christ as the Messiah, either by falling back on the comfortable familiarity of Judaism (as did the crippled man) or misunderstanding the nature of Jesus’ authority (like the crowd that were fed), the reader is better able to understand what it means to believe. They can also empathise with Jesus’ frustration at the fact that he is not producing the effect he intended, even having performed great miracles before people’s eyes, and so begin to know Jesus as a person as well as his divinity.
Another objection to the statement in the title is that John includes many details that seem to serve no other purpose than to document the particulars of the sign. For example, in the third sign, there is mention of the Sheep Gate at the Pool in Bethsaida, the five stone colonnades and the fact that the man in question had been crippled for 38 years.
However, these are not necessarily included by John for the sake of being historically and topographically accurate. Some details could be symbolic. For example, Marsh suggests that the 38 years could be a deliberate parallel to the 40 days that Moses spent wandering the desert. This parallel might be intended as a subtle message to the reader that Christ has fulfilled Judaism, making it good, just as Jesus makes the crippled man better in the sign. The details that John includes in the signs may also be a way of validating them and convincing the reader that Jesus’ miracles did take place.
It seems that the title claim is justified, and that John’s main purpose for the signs was in fact to make his readers believe. Not only is it explicitly stated in John 20:31, but there is evidence for it throughout the signs. Whilst it appears at first that the gospel being a theological piece of writing and it being an accurate account are mutually exclusive, the two attributes do overlap. As Marsh notes, the historical and topographical details in John often give rise to symbolism and provoke theological thought, and can be just as important as the fictitious component of the signs in encouraging faith in the reader.