They knew not - That is, they knew not the exact time until it came upon them. So, says he, it shall be when the Son of man shall come. They shall not know "the precise time" until he comes, and then they will be found engaged in the ordinary business of life unconcerned.

And knew not - They considered not - did not lay Noah's warning to heart, till it was too late to profit by it: so shall it be - and so it was in this coming of the Son of man.

And knew not until the flood came,.... That is, they did not advert or give heed to what Noah said to them about it: they slighted and despised his warnings; they did not believe, that what he said of the flood was true; they had notice of it, but they would not know it, and therefore God gave them up to judicial blindness and hardness of heart; and so they remained, until it came upon them at once:

and took them all away; the whole world of the ungodly, every man, woman, and child, except eight persons only; Noah and his wife, and his three sons and their wives; for the deluge was universal, and reached to all the inhabitants of the world, who all perished in it, excepting the above persons,

So shall also the coming of the son of man be: such shall be, as it was, the case of the Jews, before the destruction of Jerusalem: they gave themselves up to all manner of wickedness and uncleanness; they disregarded the warnings of Christ and his apostles; they were careless and secure of danger; they would not believe their ruin was at hand, when it was just upon them; they buoyed themselves up to the very last, that a deliverer would arise, and save them; they cried peace, peace, when sudden destruction was nigh; even of them all, their nation, city, and temple, a few only excepted, as in the days of Noah: and though they were so much like the men of that generation, yet they themselves say of them, that "the generation of the flood have no part in the world to come, nor shall they stand in judgment, according to Genesis 6:3 (o).

(o) Misn. Sanhedrin, c. 11. sect. 3.

And knew not until the flood came, and took them all away; so shall also the coming of the Son of man be.

Margin Son of man

See Scofield Note: "Mt 8:20"

24:29-41 Christ foretells his second coming. It is usual for prophets to speak of things as near and just at hand, to express the greatness and certainty of them. Concerning Christ's second coming, it is foretold that there shall be a great change, in order to the making all things new. Then they shall see the Son of man coming in the clouds. At his first coming, he was set for a sign that should be spoken against, but at his second coming, a sign that should be admired. Sooner or later, all sinners will be mourners; but repenting sinners look to Christ, and mourn after a godly sort; and those who sow in those tears shall shortly reap in joy. Impenitent sinners shall see Him whom they have pierced, and, though they laugh now, shall mourn and weep in endless horror and despair. The elect of God are scattered abroad; there are some in all places, and all nations; but when that great gathering day comes, there shall not one of them be missing. Distance of place shall keep none out of heaven. Our Lord declares that the Jews should never cease to be a distinct people, until all things he had been predicting were fulfilled. His prophecy reaches to the day of final judgment; therefore he here, ver. 34, foretells that Judah shall never cease to exist as a distinct people, so long as this world shall endure. Men of the world scheme and plan for generation upon generation here, but they plan not with reference to the overwhelming, approaching, and most certain event of Christ's second coming, which shall do away every human scheme, and set aside for ever all that God forbids. That will be as surprising a day, as the deluge to the old world. Apply this, first, to temporal judgments, particularly that which was then hastening upon the nation and people of the Jews. Secondly, to the eternal judgment. Christ here shows the state of the old world when the deluge came. They were secure and careless; they knew not, until the flood came; and they believed not. Did we know aright that all earthly things must shortly pass away, we should not set our eyes and hearts so much upon them as we do. The evil day is not the further off for men's putting it far from them. What words can more strongly describe the suddenness of our Saviour's coming! Men will be at their respective businesses, and suddenly the Lord of glory will appear. Women will be in their house employments, but in that moment every other work will be laid aside, and every heart will turn inward and say, It is the Lord! Am I prepared to meet him? Can I stand before him? And what, in fact, is the day of judgment to the whole world, but the day of death to every one?