“A man without persistence will never make a good shaman or a good physician.”

The Wanderer of Switzerland, Part v. Compare: "Say not that the good die" (translated from original Greek), Callimachus, Epigram x.
Bartlett's Familiar Quotations, 10th ed. (1919).

Source: Stranger in a Strange Land

Of Anger.
Political, Moral, and Miscellaneous Reflections (1750), Political Thoughts and Reflections

Source: Buying a Fishing Rod for My Grandfather (2005), p. 103

Book III, 1276b.34
Politics

The Second World War, Volume I : The Gathering Storm (1948) Chapter 17 (The Tragedy of Munich), p .287 http://books.google.de/books?id=HzlT3t05OHoC&pg=PA287&dq=churchill+the+gathering+storm+have+been+averted+by+patience+and+persisting+good+will!&hl=de&sa=X&ei=1355T-39C4jHsgb0t-mWBA&ved=0CDIQ6AEwAA#v=onepage&q&f=false
Post-war years (1945–1955)
Context: Those who are prone, by temperament and character, to seek sharp and clear-cut solutions of difficult and obscure problems, who are ready to fight whenever some challenge comes from a foreign power, have not always been right. On the other hand, those whose inclination is to bow their heads, to seek patiently and faithfully for peaceful compromise, are not always wrong. On the contrary, in the majority of instances they may be right, not only morally, but from a practical standpoint. How many wars have been averted by patience and persisting good will! Religion and virtue alike lend their sanctions to meekness and humility, not only between men but between nations. How many wars have been precipitated by firebrands! How many misunderstandings which led to wars could have been removed by temporizing! How often have countries fought cruel wars and then after a few years found themselves not only friends but allies!

Light, Power and Wisdom (1959), p. 6; note that the short phrase "Be good, do good" had occurred in spiritual teachings of others in the 19th century, usually in conjunction with other injunctions. "Be Good, Do Good" became a prominent motto of the Divine Life Society.
Light, Power and Wisdom (1959), p. 207
Variant: Be good, do good, be kind, be compassionate.

Source: Brevia: Short Essays and Aphorisms. (1871), p.31.