A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
luk 17:1OFFENSES--FAITH--HUMILITY. (Luk 17:1-10)
(See Mat 18:6-7).
luk 17:3(See on Mat 18:15-17; Mat 18:21-22).
luk 17:4seven times--not a lower measure of the forgiving spirit than the "seventy times seven" enjoined on Peter, which was occasioned by his asking if he was to stop at seven times. "No," is the virtual answer, "though it come to seventy times that number, if only he ask forgiveness in sincerity."
luk 17:5Lord--(See on Luk 10:1).
increase our faith--moved by the difficulty of avoiding and forgiving "offenses." This is the only instance in which a spiritual operation upon their souls was solicited of Christ by the Twelve; but a kindred and higher prayer had been offered before, by one with far fewer opportunities. (See on Mar 9:24.)
luk 17:6sycamine--mulberry. (See on Mar 11:22-24.)
luk 17:7say unto him by and by--The "by and by" (or rather "directly") should be joined not to the saying but the going: "Go directly." The connection here is: "But when your faith has been so increased as both to avoid and forgive offenses, and do things impossible to all but faith, be not puffed up as though you had laid the Lord under any obligations to you."
luk 17:9I trow not--or, as we say, when much more is meant, "I should think not."
luk 17:10unprofitable--a word which, though usually denoting the opposite of profit, is here used simply in its negative sense. "We have not, as his servants, profited or benefited God at all." (Compare Job 22:2-3; Rom 11:35.)
luk 17:11TEN LEPERS CLEANSED. (Luk 17:11-19)
through the midst of Samaria and Galilee--probably on the confines of both.
luk 17:12stood afar off--(Compare Lev 13:45-46).
luk 17:13they lifted up--their common misery drawing these poor outcasts together (Kg2 7:3), nay, making them forget the fierce national antipathy of Jew and Samaritan [TRENCH].
Jesus, &c.--(Compare Mat 20:30-33). How quick a teacher is felt misery, even though as here the teaching may be soon forgotten!
luk 17:14show yourselves--as cleansed persons. (See on Mat 8:4.) Thus too would the Samaritan be taught that "salvation is of the Jews" (Joh 4:22).
as they went, were cleansed--In how many different ways were our Lord's cures wrought, and this different from all the rest.
luk 17:17Were there not ten cleansed--rather, were not the ten cleansed? that is, the whole of them--an example (by the way) of Christ's omniscience [BENGEL].
luk 17:18this stranger--"this alien" (literally, "of another race"). The language is that of wonder and admiration, as is expressly said of another exhibition of Gentile faith (Mat 8:10).
luk 17:19Arise--for he had "fallen down on his face at His feet" (Luk 17:16) and there lain prostrate.
faith made thee whole--not as the others, merely in body, but in that higher spiritual sense with which His constant language has so familiarized us.
luk 17:20COMING OF THE KINGDOM OF GOD AND OF THE SON OF MAN. (Luke 17:20-37)
when, &c.--To meet the erroneous views not only of the Pharisees, but of the disciples themselves, our Lord addresses both, announcing the coming of the kingdom under different aspects.
It cometh not with observation--with watching or lying in wait, as for something outwardly imposing and at once revealing itself.
luk 17:21Lo here! . . . lo there!--shut up within this or that sharply defined and visible geographical or ecclesiastical limit.
within you--is of an internal and spiritual character (as contrasted with their outside views of it). But it has its external side too.
luk 17:22The days--rather "Days."
will come--as in Luk 19:43, when, amidst calamities, &c., you will anxiously look for a deliverer, and deceivers will put themselves forward in this character.
one of the days of the Son of man--Himself again among them but for one day; as we say when all seems to be going wrong and the one person who could keep them right is removed [NEANDER in STIER, &c.]. "This is said to guard against the mistake of supposing that His visible presence would accompany the manifestation and establishment of His kingdom" [WEBSTER and WILKINSON].
luk 17:23they shall say, See here . . . go not, &c.--a warning to all so-called expositors of prophecy and their followers, who cry, Lo there and see here, every time that war breaks out or revolutions occur.
luk 17:24as lightning . . . so . . . the Son of man--that is it will be as manifest. The Lord speaks here of His coming and manifestation in a prophetically indefinite manner, and in these preparatory words blends into one the distinctive epochs [STIER]. When the whole polity of the Jews, civil and ecclesiastical alike, was broken up at once, and its continuance rendered impossible by the destruction of Jerusalem, it became as manifest to all as the lightning of heaven that the kingdom of God had ceased to exist in its old, and had entered on a new and perfectly different form. So it may be again, ere its final and greatest change at the personal coming of Christ, and of which the words in their highest sense are alone true.
luk 17:25But first . . . suffer, &c.--This shows that the more immediate reference of Luk 17:23 is to an event soon to follow the death of Christ. It was designed to withdraw the attention of "His disciples" from the glare in which His foregoing words had invested the approaching establishment of His kingdom.
luk 17:26eat . . . married . . . planted--all the ordinary occupations and enjoyments of life. Though the antediluvian world and the cities of the plain were awfully wicked, it is not their wickedness, but their worldliness, their unbelief and indifference to the future, their unpreparedness, that is here held up as a warning. Note.--These recorded events of Old Testament history--denied or explained away nowadays by not a few--are referred to here as facts.
luk 17:31to take it away . . . Remember, &c.--a warning against that lingering reluctance to part with present treasures which induces some to remain in a burning house, in hopes of saving this and that precious article till consumed and buried in its ruins. The cases here supposed, though different, are similar.
luk 17:32Lot's wife--her "look back," for that is all that is said of her, and her recorded doom. Her heart was in Sodom still, and the "look" just said, "And must I bid it adieu?"
luk 17:33Whosoever, &c.--(See on Luk 9:23-27).
luk 17:34two in one bed--the prepared and unprepared mingled in closest intercourse together in the ordinary walks and fellowships of life, when the moment of severance arrives. Awful truth! realized before the destruction of Jerusalem, when the Christians found themselves forced by their Lord's directions (Luk 21:21) at once and for ever away from their old associates; but most of all when the second coming of Christ shall burst upon a heedless world.
luk 17:37Where--shall this occur?
Wheresoever, &c.--"As birds of prey scent out the carrion, so wherever is found a mass of incurable moral and spiritual corruption, there will be seen alighting the ministers of divine judgment," a proverbial saying terrifically verified at the destruction of Jerusalem, and many times since, though its most tremendous illustration will be at the world's final day.