“We believe that the time has come for doing more fully what He has commanded us; and by His grace we intend to do it. Not to try, for we see no Scriptural authority for trying. Try is a word constantly in the mouth of unbelievers,... far too often taken up by believers. In our experience, ‘to try’ has usually meant ‘to fail’. (The Lord’s) command is not ‘Do your best,’ but ‘DO IT’.”

1960, The New Frontier
Context: For the harsh facts of the matter are that we stand on this frontier at a turning-point in history. We must prove all over again whether this nation — or any nation so conceived — can long endure — whether our society — with its freedom of choice, its breadth of opportunity, its range of alternatives — can compete with the single-minded advance of the Communist system. Can a nation organized and governed such as ours endure? That is the real question. Have we the nerve and the will? Can we carry through in an age where we will witness not only new breakthroughs in weapons of destruction — but also a race for mastery of the sky and the rain, the ocean and the tides, the far side of space and the inside of men's minds? Are we up to the task — are we equal to the challenge? Are we willing to match the Russian sacrifice of the present for the future — or must we sacrifice our future in order to enjoy the present? That is the question of the New Frontier. That is the choice our nation must make — a choice that lies not merely between two men or two parties, but between the public interest and private comfort — between national greatness and national decline — between the fresh air of progress and the stale, dank atmosphere of "normalcy" — between determined dedication and creeping mediocrity. All mankind waits upon our decision. A whole world looks to see what we will do. We cannot fail their trust, we cannot fail to try.

As quoted in The Subconscious Diet : It's Not What You Put in Your Mouth; It Is What You Put in Your Mind (2005) by Hugh B. Sanders, p. 104 <!-- also quoted in The First Step : A Peek at the Real World (2006) by Gudmundur O. Sigurdarson, p. 41 -->
Context: Success means doing the best we can with what we have. Success is the doing, not the getting — in the trying, not the triumph. Success is a personal standard — reaching for the highest that is in us — becoming all that we can be. If we do our best, we are a success. Success is the maximum utilization of the ability that you have.

"That's What Love Is For", co-written with Michael Omartian and Mark Mueller
Song lyrics, Heart in Motion (1991)

15 March 2012 https://twitter.com/gtdguy/status/180374838857318400
Official Twitter profile (@gtdguy) https://twitter.com/gtdguy

"Preface", as translated by Barbara Green and Reihhard Krauss (2001). <!-- Edited by Geffrey B. Kelly and John D. Godsey -->
Discipleship (1937)
Context: Should the church be trying to erect a spiritual reign of terror over people by threatening earthly and eternal punishment on its own authority and commanding everything a person must believe and do to be saved? Should the church's word bring new tyranny and violent abuse to human souls? It may be that some people yearn for such servitude. But could the church ever serve such a longing?
When holy scripture speaks of following Jesus, it proclaims that people are free from all human rules, from everything which presumes, burdens, or causes worry and torment of conscience. In following Jesus, people are released from the hard yoke of their own laws to be under the gentle yoke of Jesus Christ. … Jesus' commandment never wishes to destroy life, but rather to preserve, strengthen, and heal life.

The grand old man of American psychiatry on what he has learnt about life (and death) in his still-flourishing career, The Independent http://www.independent.co.uk/news/people/profiles/irvin-d-yalom-interview-the-grand-old-man-of-american-psychiatry-on-what-he-has-learnt-about-life-10134092.html

Epilogue, p. 221
Eat and Run (2012)

As quoted in "Campaigning with Grant" http://books.google.com/books?id=Y7TPAAAAMAAJ&q=&quot;Oh+I+am+heartily+tired+of+hearing+about+what+Lee+is+going+to+do+Some+of+you+always+seem+to+think+he+is+suddenly+going+to+turn+a+double+somersault+and+land+in+our+rear+and+on+both+of+our+flanks+at+the+same+time+Go+back+to+your+command+and+try+to+think+what+we+are+going+to+do+ourselves+instead+of+what+Lee+is+going+to+do&quot;&pg=PA230#v=onepage (December 1896), by General Horace Porter, The Century Magazine
1860s

Daily Telegram #1172, Will Rogers Sees No Value In All The Time We Save (28 April 1930)
Daily telegrams