“With great employments and vulgar maxims, one is always restless and uneasy : it is not places, but reason, that removes anxiety from the mind.”
Source: A Mother's Advice to Her Son, 1726, p. 170
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Anne-Thérèse de Marguenat de Courcelles, marquise de Lambert 23
writer from France 1647–1733Related quotes

“Nothing so comforts the military mind as the maxim of a great but dead general.”
Source: The Guns of August

Quoted, This Side of Paradise (1920)
Context: I simply state that I'm a product of a versatile mind in a restless generation — with every reason to throw my mind and pen in with the radicals. Even if, deep in my heart, I thought we were all blind atoms in a world as limited as a stroke of a pendulum, I and my sort would struggle against tradition; try, at least, to displace old cants with new ones. I've thought I was right about life at various times, but faith is difficult. One thing I know. If living isn't seeking for the grail it may be a damned amusing game.

Can it alter the cause, or unravel the mystery of human events?
Misattributed to Tryon Edwards by a number of websites, thinkexist.com and quoteland.com among others. This quote does appear on p. 23 of Edwards' compilation, A Dictionary of Thoughts; however, it is clearly identified there as a quote by Hugh Blair, the Scottish author and preacher.
A genuine Tryon Edwards quote on the subject of anxiety appears above in the Sourced section ( from p. 22 of A Dictionary of Thoughts. )
Misattributed

Can it alter the cause, or unravel the mystery of human events?
Quoted in A Dictionary of Thoughts: Being a Cyclopedia of Laconic Quotations from the Best Authors of the World, Both Ancient and Modern, https://books.google.com/books?id=zlMxAAAAIAAJ ed. Tryon Edwards, F. B. Dickerson Company (1908), p. 23.

Source: Anwarul Ulum, vol. 13, p. 94, Meri Sarah, p. 23

First Treatise of Government
Two Treatises of Government (1689)
Context: The imagination is always restless and suggests a variety of thoughts, and the will, reason being laid aside, is ready for every extravagant project; and in this State, he that goes farthest out of the way, is thought fittest to lead, and is sure of most followers: And when Fashion hath once Established, what Folly or craft began, Custom makes it Sacred, and 'twill be thought impudence or madness, to contradict or question it. He that will impartially survey the Nations of the World, will find so much of the Governments, Religion, and Manners brought in and continued amongst them by these means, that they will have but little Reverence for the Practices which are in use and credit amongst Men.

Traits and Trials of Early Life (1836)

http://books.google.com/books?id=eRwwAAAAMAAJ&q="The+two+maxims+of+any+great+man+at+court+are+always+to+keep+his+countenance+and+never+to+keep+his+word"&pg=PA262#v=onepage
Thoughts on Various Subjects from Miscellanies (1711-1726)