Charles Ellicott Commentary Ruth 4:20

"and Amminadab begat Nahshon, and Nahshon begat Salmon," — Ruth 4:20 (ASV)

Nahshon was the prince of the children of Judah in the wilderness (see Numbers 1:7 and following).

Salmon —Heb., Salmah, though called Salmon in the next verse. In 1 Chronicles 2:11 he is called Salma. Salmon may very probably have been one of the two spies sent to Jericho, who, having been sheltered by Rahab, repaid her kindness by marrying her.

It has been observed above that the small number of generations hardly suits the long period of years implied here. On the whole, we are inclined to believe that some links in the genealogical chain have been dropped, and if so, then doubtless in the period before Boaz.

Thus, we may suppose that the list here presents the distinguished names, while others of lesser note are passed over. Unless this is the case, we are forced to largely increase the average length of a generation and assume that most of these ancestors were children born to their fathers in old age. We know from 1 Kings 6:1 that the time from the Exodus to the fourth year of Solomon was 480 years.

If we deduct forty years for the wanderings in the desert from this total, then, given that David died at the age of seventy, the period from the entrance into Canaan to the birth of David is 366 years (480 - 40 - 70 - 4 = 366). However, if Rahab bore Boaz to Salmon only a few years after the beginning of this period, we would then need to cover nearly 366 years with just three generations: Boaz, Obed, and Jesse.

This would lead to the conclusion that each of these three men begot the specified son when over one hundred years old, and that Salmon was also well advanced in years at his marriage. Such a scenario, however, seems hardly credible. Therefore, the theory that one or two generations have been dropped from the list is, at any rate, reasonable.