“The material which a scientist actually has at his disposal, his laws, his experimental results, his mathematical techniques, his epistemological prejudices, his attitude towards the absurd consequences of the theories which he accepts, is indeterminate in many ways, ambiguous, and never fully separated from the historical background.”

Foreward, to "Memorial issue for Robert H. Jackson", 55 Columbia Law Review (April, 1955) p. 436; quoted by United States Senator Howell Heflin during the confirmation debate for Justice David Souter, on September 24, 1990, S13540.
Other writings

The Brass Ring (1971)
Context: If you're a leader, you don't push wet spaghetti, you pull it. The U. S. Army still has to learn that. The British understand it. Patton understood it. I always admired Patton. Oh, sure, the stupid bastard was crazy. He was insane. He thought he was living in the Dark Ages. Soldiers were peasants to him. I didn't like that attitude, but I certainly respected his theories and the techniques he used to get his men out of their foxholes.

Letter to Robert A. Thorton, Physics Professor at University of Puerto Rico (7 December 1944) [EA-674, Einstein Archive, Hebrew University, Jerusalem]. Thorton had written to Einstein on persuading colleagues of the importance of philosophy of science to scientists (empiricists) and science.
1940s
Context: I fully agree with you about the significance and educational value of methodology as well as history and philosophy of science. So many people today — and even professional scientists — seem to me like someone who has seen thousands of trees but has never seen a forest. A knowledge of the historic and philosophical background gives that kind of independence from prejudices of his generation from which most scientists are suffering. This independence created by philosophical insight is — in my opinion — the mark of distinction between a mere artisan or specialist and a real seeker after truth.

38
The Sublime Object of Ideology (1989)

Source: Skin in the Game (2018), p. 12

Contribution in Albert Einstein: Philosopher-Scientist, p. A. Schilpp, ed. (The Library of Living Philosophers, Evanston, IL (1949), p. 684). Quoted in Einstein's Philosophy of Science http://plato.stanford.edu/entries/einstein-philscience/
1940s

Comparable to remarks of William Masters, in "Two Sex Researchers on the Firing Line" LIFE magazine (24 June 1966), p. 49: "Science by itself has no moral dimension. But it does seek to establish truth. And upon this truth morality can be built."
Variants:
Science does not have a moral dimension. It is like a knife. If you give it to a surgeon or a murderer, each will use it differently.
As quoted in Futurehype: The Myths of Technology Change (2009) by Robert B. Seidensticker
Science does not have a moral dimension. It is like a knife. If you give it to a surgeon or a murderer, each will use it differently. Should the knife have not been developed?
As quoted in Science & Society (2012) by Peter Daempfle, Ch. 6, p. 97<!-- also in Good Science, Bad Science, Pseudoscience, and Just Plain Bunk: How to Tell the Difference (2013) by Peter Daempfle, Ch. 9, p. 166 -->
Responsible Scientific Investigation and Application (1976)
Context: One of the most disconcerting issues of our time lies in the fact that modern science, along with miracle drugs and communications satellites, has also produced nuclear bombs. What makes it even worse, science has utterly failed to provide an answer on how to cope with them. As a result, science and scientists have often been blamed for the desperate dilemma in which mankind finds itself today.
Science, all by itself, has no moral dimension. The same poison-containing drug which cures when taken in small doses, may kill when taken in excess. The same nuclear chain reaction that produces badly needed electrical energy when harnessed in a reactor, may kill thousands when abruptly released in an atomic bomb. Thus it does not make sense to ask a biochemist or a nuclear physicist whether his research in the field of toxic substances or nuclear processes is good or bad for mankind. In most cases the scientist will be fully aware of the possibility of an abuse of his discoveries, but aside from his innate scientific curiosity he will be motivated by a deep-seated hope and belief that something of value for his fellow man may emerge from his labors.
The same applies to technology, through which most advances in the natural sciences are put to practical use.

Source: The motivation to work, 1959, p. 5