In connection with a course I am teaching, I have prepared an accessible version of Oenomaus’ critique of deceptive oracles and placed it on archive.org: Oenomaus of Gadara, Detection of Deceivers, or Charlatans Exposed (Γοήτων φώρα). This work was cited in Eusebius, Praeparatio Evangelica = Preparation for the Gospel 5.18-36 and 6.7 (translation with modifications from Gifford, Eusebii Pamphili Evangelicae Praeparationis (Oxford: Oxford University Press, 1903)).
Oenomaus (Oinomaos) of Gadara in Palestine was a Cynic philosopher (probably in the second century CE, during the reign of Hadrian) who wrote a work against deceptive divination practices and procedures at oracles, including those at Delphi and Claros (Klaros). The work is only preserved in extracts by the church historian, Eusebius (early fourth century CE). For clarity, I present Eusebius’ own comments in italics and those attributed to Oenomaus of Gadara in regular font. Oracles cited by Oenomaus are indented. I have modernized Gifford’s English translation.
The work is especially helpful in providing context for Lucian of Samosata’s critique of the oracle of Glykon set up by Alexander of Abonouteichos, a writing also known as Alexander the False Prophet (link). Lucian aligns himself with Epicurean philosophers who likewise sought to expose the supposed deceptions of this oracle in northern Asia Minor (in Paphlagonia).