luke 18:8 I tell you that he will avenge them speedily. Nevertheless when the Son of man cometh, shall he find faith on the earth? - Free Bible Online

      8. speedily--as if pained at the long delay, impatient for the destined moment to interpose. (Compare Pr 29:1.)
      Nevertheless, &c.--that is, Yet ere the Son of man comes to redress the wrongs of His Church, so low will the hope of relief sink, through the length of the delay, that one will be fain to ask, Will He find any faith of a coming avenger left on the earth? From this we learn: (1) That the primary and historical reference of this parable is to the Church in its widowed, desolate, oppressed, defenseless condition during the present absence of her Lord in the heavens; (2) That in these circumstances importunate, persevering prayer for deliverance is the Church's fitting exercise; (3) That notwithstanding every encouragement to this, so long will the answer be delayed, while the need of relief continues the same, and all hope of deliverance will have nearly died out, and "faith" of Christ's coming scarcely to be found. But the application of the parable to prayer in general is so obvious as to have nearly hidden its more direct reference, and so precious that one cannot allow it to disappear in any public and historical interpretation.

JFB.