Full Idea
Pythagoras advised above all things to speak the truth, for this alone deifies man.
Clarification
'Deifies' means turns into a god
Gist of Idea
Speak the truth, for this alone deifies man
Source
report of Pythagoras (reports [c.530 BCE]) by Porphyry - Life of Pythagoras §41
Book Reference
'The Pythagorean Sourcebook and Library', ed/tr. Guthrie,Kenneth Sylvan [Phanes 1988], p.131
A Reaction
Idea 4421 (of Nietzsche) stands in contrast to this. I am not quite sure why speaking the truth has such a high value. I am inclined to a minimalist view, which is just that philosophy is an attempt to speak the truth, as fishermen try to catch fish.
Related Idea
Idea 4421 Philosophers have never asked why there is a will to truth in the first place [Nietzsche]