These are times in which a genius would wish to live. It is not in the still calm of life, or in the repose of a pacific station, that great characters are formed. The habits of a vigorous mind are formed in contending with difficulties. Great necessities call out great virtues.

Abigail Adams (1744–1818) American correspondent, First Lady (1797–1801)

Letter to John Quincy Adams (19 Jan 1780)

Probable source of the similar "Great necessities call forth great leaders," usually cited (but not found) as a letter to Thomas Jefferson.