'Forty' in the Bible

And Cainan lived after he begat Mahalaleel eight hundred and forty years, and begat sons and daughters:

For yet seven days, and I will cause it to rain upon the earth forty days and forty nights; and every living substance that I have made will I destroy from off the face of the earth.

And the rain was upon the earth forty days and forty nights.

And the flood was forty days upon the earth; and the waters increased, and bare up the ark, and it was lift up above the earth.

And it came to pass at the end of forty days, that Noah opened the window of the ark which he had made:

Peradventure there shall lack five of the fifty righteous: wilt thou destroy all the city for lack of five? And he said, If I find there forty and five, I will not destroy it.

And he spake unto him yet again, and said, Peradventure there shall be forty found there. And he said, I will not do it for forty's sake.

And Isaac was forty years old when he took Rebekah to wife, the daughter of Bethuel the Syrian of Padanaram, the sister to Laban the Syrian.

And Esau was forty years old when he took to wife Judith the daughter of Beeri the Hittite, and Bashemath the daughter of Elon the Hittite:

Thirty milch camels with their colts, forty kine, and ten bulls, twenty she asses, and ten foals.

And Jacob lived in the land of Egypt seventeen years: so the whole age of Jacob was an hundred forty and seven years.

And forty days were fulfilled for him; for so are fulfilled the days of those which are embalmed: and the Egyptians mourned for him threescore and ten days.