And the rain was upon the earth. Although the Lord burst open the floodgates of the waters, yet he does not allow them to break forth in a moment, so as immediately to overwhelm the earth, but causes the rain to continue forty days; partly, that Noah, by long meditation, might more deeply fix in his memory what he had previously learned, by instruction, through the word; partly, that the wicked, even before their death, might feel that those warnings which they had held in derision, were not empty threats. For they who had so long scorned the patience of God, deserved to feel that they were gradually perishing under that righteous judgment of his, which, during a hundred years, they had treated as a fable. And the Lord frequently so tempers his judgments, that men may have leisure to consider with more advantage those judgments which, by their sudden eruption, might overcome them with astonishment. But the wonderful depravity of our nature shows itself in this, that if the anger of God is suddenly poured forth, we become stupefied and senseless; but if it advances with measured pace, we become so accustomed to it as to despise it; because we do not willingly acknowledge the hand of God without miracles; and because we are easily hardened, by a kind of superinduced insensibility, at the sight of God's works.

The rain was upon the earth - Dr. Lightfoot supposes that the rain began on the 18th day of the second month, or Marcheshvan, and that it ceased on the 28th of the third month, Cisleu.

And the rain was upon the earth forty days and forty nights,.... So long it was falling upon it, after the windows of heaven were opened. Aben Ezra would have it, that all things were in such confusion, during the flood, that there was no difference between day and night, since, it is said, "day and night shall not cease any more"; and that after the waters ceased, then Noah knew that forty days and nights had passed, for God had revealed this secret to him; but the text seems more to make against him than for him.

It rained without intermission or abatement, forty days and forty nights - And that upon the whole earth at once.