PMT 2015-078 by Kenneth L. Gentry, Jr.
In Luke 18:8 Jesus makes a statement that seems to undermine any notion of the postmillennial hope. There we read:
“I tell you that He will avenge them speedily. Nevertheless, when the Son of Man comes, will He really find faith on the earth?”
Dispensationalists employ this verse with great confidence against postmillennialism. And we can certainly see why. Consider the following comments by dispensationalists.
Wayne House and Thomas Ice: “This is ‘an inferential question to which a negative answer is expected.’ So this passage is saying that at the second coming Christ will not find, literally, ‘the faith’ upon the earth.”
Hal Lindsey writes: “In the original Greek, this question assumes a negative answer. The original text has a definite article before faith, which in context means ‘this kind of faith.’”
Borland agrees: “The faith spoken of is probably the body of truth, or revealed doctrine, since the word is preceded by the definite article in the original. Improvement in the worldwide spiritual climate is not here predicted.”
Wiersbe follows suit: “The end times will not be days of great faith.” 
This verse is also brought out by amillennialists, such as R. B. Kuiper, Herman Hanko, Donald Bloesch, and Kim Riddlebarger,  as well as premillennialists such as Wayne Grudem.  Indeed, amillennialist D. Martyn Lloyd-Jones dogmatically asserts: “There is one verse, one statement, which, as far as I am concerned, is enough to put the postmillennial view right out. It is Luke 18:8.”  Bloesch declares that postmillennialism “flatly contradicts Jesus’ intimation” here in Luke 18:8. 
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But things are not what they appear to be. So I would like to note several avenues of rebuttal. As postmillennialists, we may, in fact, be warmed and filled!
First, we must determine the focus of the question.
Some doubt exists regarding whether this question is even dealing with Christianity’s future existence as such. In the context, the Lord is dealing with the matter of fervent prayer. The definite article that Borland thinks must refer to “the body of truth, or revealed doctrine” seems rather to refer to the faith in prayer evidenced in the importune widow’s persistence: “Then He spoke a parable to them, that men always ought to pray and not lose heart” (Lk 18:1). Here Christ is asking if that sort of persistent prayer will continue after he is gone.
B. B. Warfield demonstrates that the reference to “the faith” has to do with the faith-trait under question in the parable: perseverance. He doubts the reference even touches on whether or not the Christian faith will be alive then, but rather: Will Christians still be persevering in the hope of the Lord’s vindicating their cause? As in Matthew 7:13–14, He was urging them to keep persevering.  This interpretation of the meaning of “the faith,” appears among non-premillennialists, as well as premillennialists and even some dispensationalists. 
Second, we must determine the expectation in the question.
Even if it does refer to the Christian faith or the system of Christian truth, why is a negative prospect expected? As with the Matthew 7:13–14 passage, could not Christ be seeking to motivate his people, encouraging them to understand that the answer issues forth in an optimistic prospect? In another context was not Peter’s answer to such a query optimistic (Jn 6:67, 68)? Could it not be that the question is asked for the purpose not of speculation but of self-examination?
In point of fact, the question does not “assume” a negative answer at all. It is not a rhetorical question. The Funk-Blass-Debrunner Greek grammar notes that when an interrogative particle is used, as in Luke 18:8, “ou is employed to suggest an affirmative answer, me (meti) a negative reply” (p. 226 § 440). But neither of these particles occurs here. Thus, the implied answer to the question is “ambiguous” (p. 226), because the Greek word used here (ara) implies only “a tone of suspense or impatience in interrogation” (BAGD, 127).
Third, we must determine the terminus in view in the question.
Apparently, Christ has in mind his imminent coming in judgment upon Israel, not his distant second advent to end history. Christ clearly speaks of a soon vindication of his people, who cry out to him: “I tell you that He will avenge them speedily” (Lk 18:8a; cp. Rev 1:1; 6:9–10). He is urging his disciples to endure in prayer through the troublesome times coming upon them, just as he does in Matthew 24:13, which speaks of the first century generation (Mt 24:34). In fact, the preceding context of Luke 18 speaks of Jerusalem’s destruction (Lk 17:22–37).
Fourth, we must determine the implication of millennial views regarding the question.
In the final analysis, no evangelical millennial view supposes that absolutely no faith will exist on the earth at the Lord’s return. Yet, to read the statements I quote above regarding Luke 18:8 and its supposedly expecting a negative answer, one would surmise that Christianity will be totally and absolutely dead at his return.
Thus, non-postmillennialists cannot successfully employ this passage against postmillennialism. Its standard is misinterpreted: The Lord’s teaching regarding fervent prayer is changed into a warning regarding Christianity’s future. Its grammar is misconstrued: The grammar indicating concern becomes an instrument of doubt. Its goal is radically altered: Rather than speaking of soon-coming events, it supposedly points to history’s distant end. Its final result is overstated (even if all the preceding points be dismissed): No critic of postmillennialism teaches that “the faith” will entirely and completely vanish from the earth at Christ’s Return.
There now. I feel better already!
1. House and Ice, Dominion Theology, 229. Lindsey, The Road to Holocaust, 48. Borland in Liberty Commentary on the New Testament, 160. Wiersbe, Bible Exposition Commentary, 2:249.
2. Kuiper, God-Centered Evangelism, 209. Hanko, “An Exegetical Refutation of Postmillennialism,” 16. Bloesch, Last Things, 57. Riddlebarger, Case for Amillennialism, 237.
3. Grudem, Systematic Theology, 1124.
4. Lloyd-Jones, The Church and the Last Things, 217.
5. Bloesch, Last Things, 103.
6. Warfield, “The Importune Widow and the Alleged Failure of Faith,” in Warfield, Selected Shorter Writings of Benjamin B. Warfield, 2:698–710. See also: Marshall, Luke, 676.
7. Hendriksen, Luke, 818. Green, Luke, 642–43. Evans, Luke, NIBC. Nolland, Luke, 870.
8. Alford, Luke, 614. Robertson, Word Pictures, 2:232. Bock, Luke 2:1455–56.
9. Funk, A Greek Grammar of the New Testament, 226 (§ 440).