“No barriers, no masses of matter, however enormous, can withstand the powers of the mind. The remotest corners yield to them; all things succumb, the very heaven itself is laid open.”

i.254-255
Paradise Lost (1667)
Variant: The mind is its own place, and in itself
Can make a heav'n of hell, a hell of heav'n.
Source: Paradise Lost: Books 1-2

Source: Brave New World

Letter to Roger C. Weightman http://www.rjgeib.com/thoughts/jefferson/jefferson.html, declining to attend July 4th ceremonies in Washington D.C. celebrating the 50th anniversary of Independence, because of his health. This was Jefferson's last letter http://www.rjgeib.com/thoughts/jefferson/jefferson.html. (24 June 1826)
1820s
Context: All eyes are opened, or opening, to the rights of man. The general spread of the light of science has already laid open to every view the palpable truth, that the mass of mankind has not been born with saddles on their backs, nor a favored few booted and spurred, ready to ride them legitimately, by the grace of God. These are grounds of hope for others. For ourselves, let the annual return of this day forever refresh our recollections of these rights, and an undiminished devotion to them.

Woman in the Nineteenth Century (1845)
Context: We would have every arbitrary barrier thrown down. We would have every path laid open to Woman as freely as to Man. Were this done, and a slight temporary fermentation allowed to subside, we should see crystallizations more pure and of more various beauty. We believe the divine energy would pervade nature to a degree unknown in the history of former ages, and that no discordant collision, but a ravishing harmony of the spheres, would ensue.
Yet, then and only then will mankind be ripe for this, when inward and outward freedom for Woman as much as for Man shall be acknowledged as a right, not yielded as a concession.

Source: Rich Dad, Poor Dad

quality
Gesammelte Mathematische Werke (1876)

Source: The Five People You Meet in Heaven - Meniti Bianglala

Source: The Heart of Buddhist Meditation (1965), p. 21
Context: It is a significant fact and worth pondering upon that the Bible commences with the words: “In the beginning God created the heaven and the earth....", while the Dhammapada … opens with the words "Mind precedes things, dominates them, creates them". These momentous words are the quiet and uncontending, but unshakeable reply of the Buddha to that biblical belief. Here the roads of these two religions part: the one leads far away into an imaginary Beyond, the other leads straight home, into man's very heart.

The Bookshop (1978)