Here it is; “The constitution only works if it is followed by a religious and moral people.”
Here are a few that might work:
On the Importance of Morality and Religion in Government:
[W]e have no government armed with power capable of contending with human passions unbridled by morality and religion....Our constitution was made only for a moral and religious people. It is wholly inadequate to the government of any other. (Source: John Adams, The Works of John Adams, Second President of the United States, Charles Francis Adams, editor (Boston: Little, Brown, and Co. 1854), Vol. IX, p. 229, October 11, 1798.)
Religion and good morals are the only solid foundation of public
liberty and happiness.”
— Samuel Adams (letter to John Trumbull, 16 October 1778)”
Of all the dispositions and habits which least to political
prosperity, Religion and morality are indespensable supports.
In vain would that man claim the tribute of Patriotism who should
labor to subvert these great Pilliars of human happiness.
— George Washington (Farewell Address, 19 September 1796)
“[O]ur ancestors established their system of government on morality and religious sentiment. Moral habits, they believed, cannot safely be trusted on any other foundation than religious principle, nor any government be secure which is not supported by moral habits.”
— Daniel Webster, American Jurist and Senator
“[W]hen People are universally ignorant, and debauched in their Manners,
they will sink under their own weight without the Aid of foreign
Invaders.” —Samuel Adams
And my very favorite:
“Men are qualified for civil liberty in exact proportion to their disposition to put moral chains upon their own appetites—in proportion as their love of justice is above their rapacity;—in proportion as their soundness and sobriety of understanding is above their vanity and presumption;—in proportion as they are more disposed to listen to the counsels of the wise and good, in preference to the flattery of knaves. Society cannot exist, unless a controlling power upon the will and appetite is placed somewhere: and the less of it there is within, the more there must be without. It is ordained in the eternal constitution of things, that men of intemperate minds can not be free. Their passions forge their fetters.”
— Edmund Burke