What I do say is that no man is good enough to govern another man without that other’s consent. I say this is the leading principle, the sheet-anchor of American republicanism. […] According to our ancient faith, the just powers of governments are derived from the consent of the governed. Now the relation of master and slave is pro tanto a total violation of this principle. The master not only governs the slave without his consent, but he governs him by a set of rules altogether different from those which he prescribes for himself. Allow all the governed an equal voice in the government, and that, and that only, is self-government.

Abraham Lincoln (1809-1865) American lawyer, politician, US President (1861-65)

Speech (1854-10-16), “In Reply to Senator Douglas,” Peoria, Illinois
    (Source)

Speaking on the 1854 Kansas-Nebraska Act, which repealed the Missouri Compromise and allowed as "self-government" for residents of those two territories to decide locally whether to allow slavery there.

In the ellipses, Lincoln quotes the beginning of the Declaration of Independence, through "deriving their just powers from the consent of the governed."