“The greatest philosophical genius Judaism has given to the world, Spinoza, is the only one of the great philosophers for whom, in reality, God is the sole subject of thought;…”

Arne Næss, Spinoza and Ecology
M - R

From the Author's Preface to First Edition (1918)
Space—Time—Matter (1952)
Context: It was my wish to present this great subject as an illustration of the itermingling of philosophical, mathematical, and physical thought, a study which is dear to my heart. This could be done only by building up the theory systematically from the foundations, and by restricting attention throughout to the principles. But I have not been able to satisfy these self-imposed requirements: the mathematician predominates at the expense of the philosopher.

Gilles Deleuze, Expressionism in Philosophy: Spinoza (cited in the Internet Encyclopedia of Philosophy http://www.iep.utm.edu/d/deleuze.htm#SH3b)

Source: In Job's Balances: on the sources of the eternal truths, Foreword p. xxxix

Ralph Waldo Emerson, in his journal entry
A - F

De Pace Fidei (The Peace of Faith) (1453)

Original: (de) Ein Philosoph, der keine Beziehung zur Geometrie hat, ist nur ein halber Philosoph, und ein Mathematiker, der keine philosophische Ader hat, ist nur ein halber Mathematiker.

Gottlob Frege: Erkenntnisquellen der Mathematik und der mathematischen Naturwissenschaften, 1924/1925, submitted to Wissenschaftliche Grundlagen; posthumously published in: Frege, Gottlob: Nachgelassene Schriften und Wissenschaftlicher Briefwechsel. Felix Meiner Verlag, 1990, p. 293

Gilles Deleuze, Negotiations (cited in the Internet Encyclopedia of Philosophy http://www.iep.utm.edu/d/deleuze.htm#SH3b)
A - F, Gilles Deleuze

Preface
Spinoza's Critique of Religion (1965)