“Every physicist (naturally, this equally applies to other specialities, but I re- strict myself to physicists for definitiveness) should simultaneously know, apart from theoretical physics, a wealth of facts from different branches of physics and be familiar with the newest notable accomplishments.”
in his Nobel lecture http://nobelprize.org/nobel_prizes/physics/laureates/2003/ginzburg-lecture.html, December 8, 2003, at Aula Magna, Stockholm University.
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Vitaly Ginzburg 2
Russian Physicist 1916–2009Related quotes
[Physics Today, A Lowbrow's View of Feynman, 42, 2, 1989, 10.1063/1.881197] (p. 85)

"Interview with George Gamow" http://www.aip.org/history/ohilist/4325.html, by Charles Weiner at Professor Gamow's home in Boulder, Colorado (25 April 1968)

“Physics is too difficult for physicists!”
This quote has many variants. An early version attributed to the Göttingen School appears in a book review by Heinrich Wieleitner in Isis, Volume 7, No. 4, December 1925, p. 597: Ach, die Physik! Die ist ja für die Physiker viel zu schwer! (Oh, physics! That's just too difficult for the physicists!).
Disputed

“Physics is, hopefully, simple. Physicists are not.”
Conversations on the Dark Secrets of Physics (1991) by Edward Teller, Wendy Teller and Wilson Talley, Ch. 10, p. 150 footnote

As quoted in American Journal of Physics, Vol. 14 | (1946), p. 248

"David J. Gross - Biographical" http://www.nobelprize.org/nobel_prizes/physics/laureates/2004/gross-bio.html, Nobel Prize in Physics, nobelprize.org (2004)

Interview with Dr. P. A. M. Dirac by Thomas S. Kuhn at Dirac's home, Cambridge, England, May 7, 1963 http://www.aip.org/history/ohilist/4575_3.html

“... like most physicists, I really enjoy talking about physics.”
[A Conversation with Nima Arkani-Hamed: The Power of Principles, Physics Revealed (Part I), April 2, 2021, Ideas Roadshow, YouTube, https://www.youtube.com/watch?v=h6_iJRY6nU4] (quote at 2:47 of 57:39)