Adam Clarke on Luke 17:2

A mill-stone - That drowning a person with a stone tied about the neck was an ancient mode of punishment, see proved in the note on Mat 18:6, Mat 18:7 (note), to which let the following be added. To have a mill-stone hanged about the neck, was a common proverb. "Samuel saith, A man may marry, and after that addict himself to the study of the law. Rab. Jochanan saith, No: shall he addict himself to the study of the law with a mill-stone about his neck?" The place in Aristophanes, to which the reader is referred in the note on Mat 18:6 (note), is the following: - Αραν μετεωρον εις το βαραθρον εμβαλω, Εκ του λαρυγγος εκκρεμασας ὑπερβολον "Lifting him up into the air, I will plunge him into the deep: a great stone being hung about his neck."

Aristoph. in Equit. ver. 1359.