"The power under the constitution will always be in the people. It is intrusted for certain defined purposes, and for a certain limited period, to representatives of their own choosing; and, whenever it is executed contrary to their interest, or not agreeable to their wishes, their servants can and undoubtedly will be recalled." - Letter to Bushrod Washington, November 10, 1787."  -George Washington.

“If men were angels, no government would be necessary. If angels were to govern men, neither external nor internal controuls on government would be necessary. In framing a government which is to be administered by men over men, the great difficulty lies in this: You must first enable the government to controul the governed; and in the next place, oblige it to controul itself. A dependence on the people is no doubt the primary controul on the government; but experience has taught mankind the necessity of auxiliary precautions.” Federalist Paper No. 51 6 February 1788 James Madison with Alexander Hamilton. 

"I have so much faith in the general government of the world by Providence that I can hardly conceive a transaction of such momentous importance [as the framing of the Constitution] ...should be suffered to pass without being in some degree influenced, guided, and governed by that beneficent Ruler in whom all inferior spirits live and move and have their being". NOTE: Although unable to find exact source of this quote, here is a complete list of The Papers of Benjamin Franklin.

"Whereas it appeareth that however certain forms of government are better calculated than others to protect individuals in the free exercise of their natural rights, and are at the same time themselves better guarded against degeneracy, yet experience hath shewn, that even under the best forms, those entrusted with power have, in time, and by slow operations, perverted it into tyranny; and it is believed that the most effectual means of preventing this would be, to illuminate, as far as practicable, the minds of the people at large, and more especially to give them knowledge of those facts, which history exhibiteth, that, possessed thereby of the experience of other ages and countries, they may be enabled to know ambition under all its shapes, and prompt to exert their natural powers to defeat its purposes;"  Thomas Jefferson: Bill 79, "A Bill for the More General Diffusion of Knowledge."  circa 1778 

Our History In the Beginning According to Barlett's Familiar Quotations, Sir Edmond Burke said "People will not look forward to prosperity who never look backward to their ancestors" From Reflections on the Revolution in France, 1790.