Johnny Cash's "The Legend of John Henry's Hammer"

This morning, I listened to a compilation album of Johnny Cash.  I noticed the parallelism in some lines in "The Legend of John Henry's Hammer" - "John Henry’s mammy had about a dozen babies / John Henry's pappy broke jail about a dozen times."  Because it's presented in that order - with the "dozen babies" before the "dozen" jail breaks - it sort of implies that the reason John Henry's father "broke jail" was for the sake of his children.  The very beginning of the song, where John Henry's father wakes him up to give him instructions and his hammer, hints at the same thing.