Al-Kindi

“We should not be ashamed of appreciating the truth and acquiring the truth wherever it comes from, even if it comes from remote races and different nations. For
him who seeks the truth, nothing is worthier than the truth, and the truth is neither
belittled nor demeaned by him who reports it or by him who brings it. Nobody is
demeaned by the truth, but everybody is ennobled by the truth.
We would do well—since we are striving to perfect our species and in this the truth
resides—in this book to stick to our habits in all the subjects [we have dealt with]: to
present what the ancients have dealt with completely, in the most straightforward
and easiest way for those who will follow this path, and to complete what they did
not deal with completely, following, in so doing, the custom of the language and the
usages of the time, to the best of our ability”
― Al-Kindi