John 3: 22-30, Jesus and the Baptizer

Jesus has just been recently talking to Nicodemus about spiritual birth. This has occurred in the evening, probably near Jerusalem.

John 3: 22-24, Jesus ascends as John the Baptist's ministry wanes
After this, Jesus and his disciples went out into the Judean countryside, where he spent some time with them, and baptized. 
23 Now John also was baptizing at Aenon near Salim, because there was plenty of water, and people were coming and being baptized. 
24 (This was before John was put in prison.) 

The synoptic gospels (Matthew, Mark and Luke) record Jesus' ministry beginning after John is put in prison.  John, the gospel writer, includes information about the ministry of Jesus before that time. Apparently while John was baptizing along the Jordan river, Jesus also baptized disciples.

It is not certain where Aenon and Salim were located; some suggestions are given in this Wikipedia article. Verse 26, below, will suggest that Aenon and Salim are on the west side of the Jordan.

John 3: 25-30, Jesus ascends as John the Baptist's ministry wanes
An argument developed between some of John’s disciples and a certain Jew over the matter of ceremonial washing. 
26 They came to John and said to him, “Rabbi, that man who was with you on the other side of the Jordan—the one you testified about—look, he is baptizing, and everyone is going to him.”
27 To this John replied, “A person can receive only what is given them from heaven. 
28 You yourselves can testify that I said, ‘I am not the Messiah but am sent ahead of him.’ 
29 The bride belongs to the bridegroom. The friend who attends the bridegroom waits and listens for him, and is full of joy when he hears the bridegroom’s voice. That joy is mine, and it is now complete. 30 He must become greater; I must become less.”

Here is more evidence (to me) that John's baptism repeats the initiation rites of the convert to Judaism.  The convert to Judaism would be taught about the ceremonial washings (of which "baptism" was one) and so it is natural that this conversation would turn to John's baptism and his "rival" Jesus.

But Jesus is not a rival to John.  John has been consistently pointing people to Jesus, as the One, the anointed Messiah, who is to follow him.

John the Baptizer says that he is like a friend of the bridegroom, content to support the groom, enjoying the groom's delight in his bride, without envy or jealousy. In the same way, John is happy to see people turning to Jesus. Indeed, as reported in chapter 1, John sent some of his disciples to Jesus.