A.T. Robertson Commentary Luke 17

It is impossible (ανενδεκτον εστιν). See ουκ ενδεχετα in 13:33. Alpha privative (αν-) and ενδεκτος, verbal adjective, from ενδεχομα. The word occurs only in late Greek and only here in the N.T. The meaning is inadmissible, unallowable.

But that occasions of stumbling should come (του τα σκανδαλα μη ελθειν). This genitive articular infinitive is not easy to explain. In Ac 10:25 there is another example where the genitive articular infinitive seems to be used as a nominative (Robertson, Grammar, p. 1040). The loose Hebrew infinitive construction may have a bearing here, but one may recall that the original infinitives were either locatives (-εν) or datives (-α). Τα σκανδαλα is simply the accusative of general reference. Literally, the not coming as to occasions of stumbling. For σκανδαλον (a trap) see on Mt 5:29; 16:23. It is here only in Luke. The positive form of this saying appears in Mt 18:7, which see.

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 Mr 9:42 which is like Mt 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 Lu 15:7.

If thy brother sin (εαν αμαρτη). Second aorist (ingressive) subjunctive in condition of third class.

Seven times in a day (επτακις της ημερας). Seven times within the day. On another occasion Peter's question (Matthew 18:21) brought Christ's answer "seventy times seven" (verse 22), which see. Seven times during the day would be hard enough for the same offender.

Increase (προσθες). Second aorist active imperative of προστιθημ, to add to. Bruce thinks that this sounds much like the stereotyped petition in church prayers. A little reflection will show that they should answer the prayer themselves.