Matthew 24:39

39.And knew not until the deluge came. The source and cause of their ignorance was, that unbelief had blinded their minds; as, on the other hand, we are informed by the Apostle, that Noah beheld at a distance, by the eyes of faith, the vengeance of God which was still concealed, so as to entertain an early dread of it, (Hebrews 11:7.) And here Christ compares Noah with the rest of the world, and Lot with the inhabitants of Sodom, that believers may learn to withdraw, lest they wander and be cut off along with others. But it must be observed that the reprobate, at that time, were hardened in their wickedness, because the Lord did not show his grace to any but his servants, by giving them a salutary warning to beware in proper time. Not that information of the future deluge was altogether withheld from the inhabitants of the world—before whose eyes Noah, in building the ark for more than a hundred years, presented a warning of the approaching calamity—but because one man was specially warned, by divine revelation, of the future destruction of the whole world, and raised up to cherish the hope of salvation. Though the report of the last judgment is now widely circulated, and though there are a few persons who have been taught by God to perceive that Christ will come as a Judge in due time, yet it is proper that those persons should be aroused by this extraordinary kindness of God, and that their senses should be sharpened, lest they give themselves up to the indifference which so generally prevails. For Peter compares the ark of Noah with our baptism on this ground, that a small company of men, separated from the multitude, is saved amidst the waters, (1 Peter 3:20.) To this small number, therefore, our minds must be directed, if we desire to escape in safety.