John Calvin Commentary Luke 18:8

"I say unto you, that he will avenge them speedily. Nevertheless, when the Son of man cometh, shall he find faith on the earth?" — Luke 18:8 (ASV)

When the Son of man shall come. By these words Christ informs us that there will be no reason to wonder if people will afterwards sink under their calamities: it will be because they neglect the true remedy. He intended to prevent an offense which we are daily prone to take, when we see all things in shameful confusion. Treachery, cruelty, imposture, deceit, and violence, abound on every side; there is no regard for justice, and no shame; the poor groan under their oppressors; the innocent are abused or insulted; while God appears to be asleep in heaven. This is the reason why human nature imagines that the governance of fortune is blind. But Christ here reminds us that people are justly deprived of heavenly aid, on which they have neither knowledge nor inclination to rely. Those who do nothing but murmur against the Lord in their hearts, and who allow no place for His providence, cannot reasonably expect that the Lord will assist them.

Shall he find faith on the earth? Christ expressly foretells that, from His ascension to heaven until His return, unbelievers will abound. He means by these words that if the Redeemer does not appear so speedily, the blame for the delay will fall on people, because there will be almost no one to look for Him. If only we did not behold such a clear fulfillment of this prediction! But experience proves that even though the world is oppressed and overwhelmed by a great mass of calamities, there are few indeed in whom the least spark of faith can be discerned. Others understand the word faith to mean uprightness, but the former meaning is more consistent with the context.