“It is necessary to hope… for hope itself is happiness.”

No. 67 (6 November 1750)
The Rambler (1750–1752)
Context: Hope is necessary in every condition. The miseries of poverty, of sickness, or captivity, would, without this comfort, be insupportable; nor does it appear that the happiest lot of terrestrial existence can set us above the want of this general blessing; or that life, when the gifts of nature and of fortune are accumulated upon it, would not still be wretched, were it not elevated and delighted by the expectation of some new possession, of some enjoyment yet behind, by which the wish shall at last be satisfied, and the heart filled up to its utmost extent.

The Tragic Sense of Life (1913), X : Religion, the Mythology of the Beyond and the Apocatastasis
Context: May not the absolute and perfect eternal happiness be an eternal hope, which would die if it were realized? Is it possible to be happy without hope? And there is no place for hope once possession has been realized, for hope, desire, is killed by possession. May it not be, I say, that all souls grow without ceasing, some in a greater measure than others, but all having to pass some time through the same degree of growth, whatever that degree may be, and yet without ever arriving at the infinite, at God, to whom they continually approach? Is not eternal happiness an eternal hope, with its eternal nucleus of sorrow in order that happiness shall not be swallowed up in nothingness?

Source: Faithless

Fragmentary manuscript of a speech on free labor (17 September 1859?) http://quod.lib.umich.edu/l/lincoln/lincoln3/1:141?rgn=div1;view=fulltext; The Collected Works of Abraham Lincoln, ed. Roy P. Basler (1953), vol. 3, pp. 463–464
1850s
Context: Free labor has the inspiration of hope; pure slavery has no hope. The power of hope upon human exertion, and happiness, is wonderful. The slave-master himself has a conception of it; and hence the system of tasks among slaves. The slave whom you can not drive with the lash to break seventy-five pounds of hemp in a day, if you will task him to break a hundred, and promise him pay for all he does over, he will break you a hundred and fifty. You have substituted hope, for the rod. And yet perhaps it does not occur to you, that to the extent of your gain in the case, you have given up the slave system, and adopted the free system of labor.

Between the Bridge and the River (2006)

The Tragic Sense of Life (1913), X : Religion, the Mythology of the Beyond and the Apocatastasis
Context: Our life is a hope which is continually converting itself into memory and memory in its turn begets hope. Give us leave to live! The eternity that is like an eternal present, without memory and without hope, is death. Thus do ideas exist in the God-Idea, but not thus do men live in the living God, in the God-Man.

Source: Hopscotch

"Large group awareness training program" http://skepdic.com/lgsap.html, The Skeptic's Dictionary