Every project of a material change in a Government so complicated as ours, combined at the same time with external circumstances still more complicated, is a matter full of difficulties; in which a considerate man will not be too ready to decide; a prudent man too ready to undertake; or an honest man too ready to promise.
 Edmund Burke, Thoughts on the Cause of the Present Discontents (1770). copy citation

Context

“Our constitution stands on a nice equipoise, with steep precipices, and deep waters upon all sides of it. In removing it from a dangerous leaning towards one side, there may be a risque of oversetting it on the other. Every project of a material change in a Government so complicated as ours, combined at the same time with external circumstances still more complicated, is a matter full of difficulties; in which a considerate man will not be too ready to decide; a prudent man too ready to undertake; or an honest man too ready to promise. They do not respect the publick nor themselves, who engage for more, than they are sure that they ought to attempt, or that they are able to perform. These are my sentiments, weak perhaps, but honest and unbiassed;” source