In his Metaphysics, Aristotle says:
To say of what is, that it is not; or if what is not, that it is, is false; whilst to say of what is, that it is; and that what is not, is not, is truth.
I would not normally have suggested that truth was a value, assuming that all held to this; but given the disinformation climate of our times, it seems that truth is a value, and one not held by all. And in this situation, it seems that Aristotle was one of the first to say so. But of course he was simply paraphrasing Parmenides here; for example, in Parmenides poem, he says:
Come now, I will tell thee - and do thou hearken to my saying, the only two ways of searching that can be thought of: the first, that it is, and that it is impossible for it not to be - is the way of conviction, for truth is it companion.
The other, namely that it is not, and that something needs not be - that I tell you is a wholly untrustworthy path. For you cannot know what is not - that is impossible - nor utter it.
and possibly Parmenides was paraphrasing Zoroaster - given that there was commerce between the Greeks and Persians - and who is known for taking truth to be a religious value). For example, one of of his gathas (hymns) has:
I approach you with Good Thought, O Mazda Ahura, so that you may grant me the (blessing) of two existences, the material and that of thought. The blessing emanating from Truth, which one can put support in with comfort.