Luke 17:2

It were well for him

(λυσιτελε αυτω). An old word, but only here in the N.T., from λυσιτελης and this from λυω, to pay, and τα τελη, the taxes. So it pays the taxes, it returns expenses, it is profitable. Literally here, "It is profitable for him" (dative case, αυτω). Matthew has συμφερε (it is advantageous, bears together for).If a millstone were hanged

(ε λιθος μυλικος περικειτα). Literally, "if a millstone is hanged." Present passive indicative from περικειμα (to lie or be placed around). It is used as a perfect passive of περιτιθημ. So it is a first-class condition, determined as fulfilled, not second-class as the English translations imply. Μυλικος is simply a stone (λιθος), belonging to a mill. Here only in the text of Westcott and Hort, not in Mark 9:42 which is like Matthew 18:6 μυλος ονικος where the upper millstone is turned by an ass, which see.Were thrown

(ερριπτα). Perfect passive indicative from ριπτω, old verb. Literally, is thrown or has been thrown or cast or hurled. Mark has βεβλητα and Matthew καταποντισθη, which see, all three verbs vivid and expressive. Rather than (η). The comparative is not here expressed before η as one would expect. It is implied in λυσιτελε. See the same idiom in Luke 15:7.