When asked what people gain by telling likes, he replied, “That when they tell the truth they are not believed.”

[ἐρωτηθεὶς τί περιγίνεται κέρδος τοῖς ψευδομένοις, “ὅταν,” ἔφη, “λέγωσιν ἀληθῆ, μὴ πιστεύεσθαι.”]

Aristotle (384-322 BC) Greek philosopher

Attributed in Diogenes Laërtius, Lives and Opinions of Eminent Philosophers, Book 5. [tr. Mensch (2018)]
    (Source)

Original Greek. Alternate translations:

He was once asked, what those who tell lies gain by it; “They gain this,” said he, “that when they speak truth they are not believed.”
[tr. Yonge (1853), sec. 11]

To the question, "What do people gain by telling lies?" his answer was, "Just this, that when they speak the truth they are not believed."
[tr. Hicks (1925), sec. 17]