“Nature is an infinite sphere whose center is everywhere and whose circumference is nowhere.”

For a discussion of this quotation, which is uncertain in origin but was quoted long before Voltaire, see the following: http://symbio.trick.ca/HomeSashaOnePageBible[2016-05-29]
Misattributed

Eulogy on Benjamin Hill, United States Senate, Jan. 23, 1882.

The Kasîdah of Hâjî Abdû El-Yezdî (1870)
Context: And hold Humanity one man, whose universal agony
Still strains and strives to gain the goal, where agonies shall cease to be.
Believe in all things; none believe; judge not nor warp by "Facts" the thought;
See clear, hear clear, tho' life may seem Mâyâ and Mirage, Dream and Naught.
Abjure the Why and seek the How: the God and gods enthroned on high,
Are silent all, are silent still; nor hear thy voice, nor deign reply.
The Now, that indivisible point which studs the length of infinite line
Whose ends are nowhere, is thine all, the puny all thou callest thine.

[2007, Spiritual Perspectives and Human Facts, World Wisdom, 28, 978-1-933316-42-0]
Spiritual life, Sacred art

Source: Echoes from the Bottomless Well (1985), p. 2

The Spiral Dance: A Rebirth of the Ancient Religion of the Goddess (1979)
Context: This is the stillness behind motion, when time itself stops; the center is also the circumference of all. We are awake in the night. We turn the Wheel to bring the light. We call the sun from the womb of night. Blessed Be!

Sādhanā : The Realisation of Life http://www.spiritualbee.com/spiritual-book-by-tagore/ (1916)
Context: That side of our existence whose direction is towards the infinite seeks not wealth, but freedom and joy. There the reign of necessity ceases, and there our function is not to get but to be. To be what? To be one with Brahma. For the region of the infinite is the region of unity. Therefore the Upanishads say: If man apprehends God he becomes true. Here it is becoming, it is not having more. Words do no gather bulk when you know their meaning; they become true by being one with the idea.

Country Living and Country Thinking, reported in Bartlett's Familiar Quotations, 10th ed. (1919).

"At The End Of The Mechanical Age".
Sixty Stories (1981)