Joseph Smith made his "... religion by the sword" statement at Far West, MO. Rigdon said that any Mormon who refused fight the Missourians should be forced to do just that, in the front ranks of battle.
He and Sidney Rigdon call upon Mormon troops to ride to Diahman to protect the Saints. Four hundred soldiers march to Daviess County.
[LeSueur, Stephen C., The 1838 Mormon War in Missouri, Appendix: Chronology of Events in Missouri, 1838-1839;Broadhurst, Dale R., Mormon Chronology, http://olivercowdery.com/history/morchrn2.htm]