If so, his sermons or other activities in support of the American Revolution may be considered “qualifying service” for a Revolutionary War lineage society. A Washington Post article details such a sermon by Samuel Sherwood, the pastor of Norfield Congregational Church. Nathaniel Bartlett of Redding actually joined the Revolutionary Army as chaplain.
How do you provide “proof” of their service? If there was a public statement of belief, it may appear in the church records. Many Congregational church records were microfilmed by FamilySearch and can located using the catalog and a place name search. Some sermons were republished and can be found in propaganda reference texts. Those clergy who served as military chaplains may be listed in a publication entitled American Chaplains of the Revolution.
If they are a “new” ancestor, plan to document residence as well. Happy hunting!