I know the 1776 State Constitution of my home state of Pennsylvania guaranteed freedom faith and also contained a Christian oath for members of the state legislature.
A DECLARATION OF THE RIGHTS OF THE INHABITANTS OF THE COMMONWEALTH OR STATE OF PENNSYLVANIA
I. That all men are born equally free and independent, and have certain natural, inherent and inalienable rights, amongst which are, the enjoying and defending life and liberty, acquiring, possessing and protecting property, and pursuing and obtaining happiness and safety.
II. That all men have a natural and unalienable right to worship Almighty God according to the dictates of their own consciences and understanding: And that no man ought or of right can be compelled to attend any religious worship, or erect or support any place of worship, or maintain any ministry, contrary to, or against, his own free will and consent: Nor can any man, who acknowledges the being of a God, be justly deprived or abridged of any civil right as a citizen, on account of his religious sentiments or peculiar mode of religious worship: And that no authority can or ought to be vested in, or assumed by any power whatever, that shall in any case interfere with, or in any manner controul, the right of conscience in the free exercise of religious worship.
PLAN OR FRAME OF GOVERNMENT FOR THE COMMONWEALTH OR STATE OF PENNSYLVANIA
SECT. 10. A quorum of the house of representatives shall consist of two-thirds of the whole number of members elected; and having met and chosen their speaker, shall each of them before they proceed to business take and subscribe, as well the oath or affirmation of fidelity and allegiance hereinafter directed, as the following oath or affirmation, viz:
I do swear (or affirm) that as a member of this assembly, I will not propose or assent to any bill, vote, or resolution, which stall appear to free injurious to the people; nor do or consent to any act or thing whatever, that shall have a tendency to lessen or abridge their rights and privileges, as declared in the constitution of this state; but will in all things conduct myself as a faithful honest representative and guardian of the people, according to the best of only judgment and abilities.
And each member, before he takes his seat, shall make and subscribe the following declaration, viz:
I do believe in one God, the creator and governor of the universe, the rewarder of the good and the punisher of the wicked. And I do acknowledge the Scriptures of the Old and New Testament to be given by Divine inspiration.
And no further or other religious test shall ever hereafter be required of any civil officer or magistrate in this State.
http://avalon.law.yale.edu/18th_century/pa08.asp