You are looking for Joseph Abernathy b. March 13, 1784 d. June 10, 1871, in Shawnee Township, Cape Girardeau County, Missouri. He married Glaphira Abernathy in April 16, 1804, in Lincoln County, NC. Joab was born November 22, 1818, and November 19, 1909. I show he married four times: Mary Smith, Nancy Reed, Winny Beal, and Missouri Ann McLard. He and Mary Smith had eight children. Joseph, his father, had twelve children including Joab. Joseph's father was Robert Abernathy and so on back through the Robert Abernathy lineage. We don't know Glaphira's father yet, but I have always thought it was Battee Abernathy, son of Miles Abernathy. Battee married Mary Beale, and one of Joseph's sons was William Beal. Also Battee came with the Abernathy's to Cape Girardeau County and was living with John W. Abernathy, Joseph's son, on the 1870 census. I have no real proof though.
If you want more Abernathy information on Joab, please e-mail me since this can get quite lengthy.