[Marriner W. Merrill]
In reference to the scriptural saying, "The last shall be first and the first shall be last," it means that the Gospel was first introduced to the Jews in the days of the Savior. And in the latter days or last Dispensation the Gospel has been introduced to the Gentiles first and lastly to the Jews. Hence the saying, and it has no reference to a man's wives or family.
[Source: Notes from the Miscellaneous Record Book, 1886-1906: Selected diary notes from the journal books of Marriner Wood Merrill, http://amzn.to/newmormonstudies]