"Were it not for our tests, pure gold could not be distinguished from the impure. Were it not for tests, the courageous could not be separated from the cowardly. Were it not for tests, the people of faithfulness could not be known from the disloyal. Were it not for tests, the intellectuals and the faculties of the scholars in great colleges would not develop. Were it not for tests, sparkling gems could not be known from worthless pebbles. Were it not from tests, nothing would progress in this contingent world."
-Abdul-Baha, Divine Art of Living p. 87