This is evident in one of Jay's letters to Jedidiah Morse, where Jay wrote as follows:
Although the mere expediency of public measures may not be a proper subject for the pulpit, yet, in my opinion, it is the right and duty of our pastors to press the observance of all moral and religious duties, and to animadvert on every course of conduct which may be repugnant to them.- Letter dated January 1, 1813.
Jay is far from advocating a naked public square in his work, but his statement to Morse demonstrates a concern that pastors not address political issues beyond the specific competency of religion to address -- those issues that directly impacted on moral & religious duties. This active though restrained role was, to Jay, one that was supported by the witness of the Old Testament.
John Adams also addressed the role that religious preaching should play in the political life of the commonwealth. As he wrote prior to the formal outbreak of the American Revolution:
It is the duty of the clergy to accommodate their discourses to the times, to preach against such sins are most prevalent, and recommend such virtues as are most wanted. For example, -- if exorbitant ambition and venality are predominant, ought they not to warn their hears against those vices? If public spirit is much wanted, should they not inculcate this great virtue? If the rights and duties of Christian magistrates and subjects are disputed, should they not explain them, show their nature, ends, limitations, and restrictions, how much soever it may move the gall of Massachusettensis?- John Adams, Novanglus (1774) reprinted in In God We Trust: The Religious Beliefs and Ideas of the American Founding Fathers, ed. by Norman Cousins (Harper & Brothers: 1958), pg. 90.
For Adams as much as for Jay, the role of preachers was to stir the hearts of their listeners to do good and to emulate virtue, while not avoiding necessary public issues in an explanation of the duties that believers have in the political arena. When thinking on the role of formal religion in public life, it might be a good idea to pay attention to John Jay's sage words regarding the proper role intersection of politics and the pulpit.