Irenaeus indeed quotes the fourth book of Papias for an otherwise-unknown saying of Jesus, recounted by John the Evangelist, which Eusebius doubtless has in mind:Irenaeus, Adv. Haer. 5.33 .3–4. Another translation is given online by T. C. Schmidt, and another translation by Ben C. Smith.
Irenaeus indeed quotes the fourth book of Papias for an otherwise-unknown saying of Jesus recounted by John the Evangelist which Eusebius doubtless has in mindIrenaeus Adv Haer 533 3–4 Another translation is given online by T C Schmidt and another translation by Ben C Smith