John is depicted here as re-affirming the Lamb of God witness and based upon that some of his disciples move on to become some of Jesus’ disciples. This is clearly important to the author and so he must believe it is important to the community for which he is writing. I can only assume that this is an answer to some problem he or his community faced — likely there were a mixture of Jesus folks and Baptists folks in the community and there were disputes as to whose teachings were to be followed.
Another possibility is that these followers of John the Baptist may once have been a member of the community and split apart over issues of “whose prophet was better”. Doesn’t sound like Quakerism/Christianity to me (tongue planted firmly in his cheek).
This gives me a measure of comfort. There is a good variety of beliefs in the modern church and especially a wide range in the typical Quaker meeting as I have experienced it. It would seem a similar variety thrived in the first Christian churches as well.
I also note that three times the author felt obliged to translate for his readers what specific terms meant (Rabbi=teacher; Messiah=Anointed; Cephas=rock). The people for whom he is writing do not necessarily speak/read Aramaic or Hebrew. Aramaic was the common language of the Jews in and around Jerusalem and Galillee. It is likely the language Jesus taught in. If the membership of this community are Jewish theya re further afield. More comfy with Greek culture. This may be a mission church that John is speaking/writing to.