Ruth 4:21
Salmon was the father of Boaz,
What it says
Nahshon fathers Salmon, and Salmon fathers Boaz.
What it is doing
It brings the genealogy down to Boaz himself.
In context
18Now these are the generations of Perez: 19Hezron was the father of Ram, 20Amminadab was the father of Nahshon, 21Salmon was the father of Boaz, 22Obed was the father of Jesse,