John 1:31

‘And I did not know Him, but that he would be revealed to Israel. This was why I came baptising with water.'

‘But that He would be revealed to Israel'. John had begun to preach knowing that ‘the coming One' was to follow him, and would be made known to Israel, and that he himself was preparing the way. What he had not known was who He was nor how He would be revealed.

He admits that he had not realised at first who Jesus was, even though Jesus was his cousin, but he had come to recognises Jesus' superiority to himself (Matthew 3:14), and he now stresses that he had come to realise at Jesus' baptism that He was the One for Whom he was preparing, for he had seen the Holy Spirit descending and remaining on Him, and had realised from this that He was the One Who would drench (baptizo = drench, inundate) in the Holy Spirit as promised by the prophets.

This stresses the significance of John's baptism. It was a message in picture form illustrating the future work of Jesus. In the Old Testament the coming of the Spirit in the new age is regularly depicted in terms of rain pouring from the heavens, of floods of water, and of new fruitfulness (e.g. Isaiah 32:15; Isaiah 44:4). Thus John's baptism declares the near approach of this coming age of the Spirit, which could be seen as present in the coming of Jesus. It is an acted out parable in line with those of previous prophets.