John Gill Commentary Ruth 4:21

"and Salmon begat Boaz, and Boaz begat Obed," — Ruth 4:21 (ASV)

And Salmon begat Boaz
Of Rahab the harlot, whom he married, (Matthew 1:5) the very same person that makes a principal part of this book, and whom the Targum here takes to be the judge Ibzan, (See Gill on Ruth 1:1).

and Boaz begat Obed ;
of Ruth; of whom see the preceding verses.