“Knowledge is the product of leisure. The members of a very primitive society have no time to amass knowledge; their days are fully occupied with the provision of the bare necessities of life. But as soon as a community begins to accumulate wealth, and so becomes able to support a leisured class (priests, instructors of rich men's children), an opportunity is created for those who desire knowledge to devote their lives to its acquirement. Out of this 'curiosity to know' science is born.”

Original: (zh-CN) 什么是知识？自从有阶级的社会存在以来，世界上的知识只有两门，一门叫做生产斗争知识，一门叫做阶级斗争知识。自然科学、社会科学，就是这两门知识的结晶，哲学则是关于自然知识和社会知识的概括和总结。 note: "整顿党的作风"
Source: "Rectify the Party's Style of Work" (1942)

Source: 1990s and later, Managing in a Time of Great Change (1995), p. 205

"On Medicine, (c. 1020) http://www.fordham.edu/halsall/source/1020Avicenna-Medicine.html
Context: The knowledge of anything, since all things have causes, is not acquired or complete unless it is known by its causes. Therefore in medicine we ought to know the causes of sickness and health. And because health and sickness and their causes are sometimes manifest, and sometimes hidden and not to be comprehended except by the study of symptoms, we must also study the symptoms of health and disease. Now it is established in the sciences that no knowledge is acquired save through the study of its causes and beginnings, if it has had causes and beginnings; nor completed except by knowledge of its accidents and accompanying essentials. Of these causes there are four kinds: material, efficient, formal, and final.

Introduction
Popular Astronomy: A Series of Lectures Delivered at Ipswich (1868)

Diary (15 May 1878)
Diary and Letters of Rutherford Birchard Hayes (1922 - 1926)
Context: General education is the best preventive of the evils now most dreaded. In the civilized countries of the world, the question is how to distribute most generally and equally the property of the world. As a rule, where education is most general the distribution of property is most general.... As knowledge spreads, wealth spreads. To diffuse knowledge is to diffuse wealth. To give all an equal chance to acquire knowledge is the best and surest way to give all an equal chance to acquire property.

Source: Guide for the Perplexed (c. 1190), Part III, Ch.23
Context: The words of God are justified, as I will show, by the fact that Job abandoned his first very erroneous opinion, and himself proved that it was an error. It is the opinion which suggests itself as plausible at first thought, especially in the minds of those who meet with mishap, well knowing that they have not merited them through sins. This is admitted by all, and therefore this opinion was assigned to Job. But he is represented to hold this view only so long as he was without wisdom, and knew God only by tradition, in the same manner as religious people generally know Him. As soon as he had acquired a true knowledge of God, he confessed that there is undoubtedly true felicity in the knowledge of God; it is attained by all who acquire that knowledge, and no earthly trouble can disturb it. So long as Job's knowledge of God was based on tradition and communication, and not on research, he believed that such imaginary good as is possessed in health, riches, and children, was the utmost that men can attain; this was the reason why he was in perplexity, and why he uttered the... opinions, and this is also the meaning of his words: "I have heard of thee by the hearing of the ear; but now mine eye seeth thee. Wherefore I abhor myself, and repent because of dust and ashes" (xlii. 5, 6); that is to say, he abhorred all that he had desired before, and that he was sorry that he had been in dust and ashes; comp. "and he sat down among the ashes" (ii. 8) On account of this last utterance, which implies true perception, it is said afterwards in reference to him, "for you have not spoken of me the thing that is right, as my servant Job hath."

Source: Striking Thoughts (2000), P. 9