Statesmen, my dear Sir, may plan and speculate for liberty, but it is religion and morality alone, which can establish the principles upon which freedom can securely stand. The only foundation of a free constitution is pure virtue; and if this cannot be inspired into our people in a greater measure than they have it now, they may change their rulers and the forms of government, but they will not obtain a lasting liberty. They will only exchange tyrants and tyrannies. You cannot, therefore, be more pleasantly or usefully employed than in the way of your profession, pulling down the strong-holds of Satan. This is not cant, but the real sentiment of my heart. Remember me with much respect to your worthy family and to all friends.
John Adams, letter to Zabdiel Adams, June 21, 1776