I have often heard a quote attributed to Maimonides which goes:
“Hear the truth, whoever said it.”
What is the source for this quote?
It is from the Rambam's introduction to the Eight Chapters
Know, however, that the ideas presented in these chapters and in the following commentary are not of my own invention; neither did I think out the explanations contained therein, but I have gleaned them from the words of the wise occurring in the Midrashim, in the Talmud, and in other of their works, as well as from the words of the philosophers, ancient and recent, and also from the works of various authors, as one should accept the truth from whatever source it proceeds (ושמע האמת ממי שאמרו).