40 Andrew, Simon Peter’s brother, was one of the two who heard what John had said and who had followed Jesus.

Read John 1:40 Using Other Translations

One of the two which heard John speak, and followed him, was Andrew, Simon Peter's brother.
One of the two who heard John speak and followed Jesus was Andrew, Simon Peter's brother.
Andrew, Simon Peter’s brother, was one of these men who heard what John said and then followed Jesus.