Phyllis
The number 40 indicates a complete change:
40 years in the Midbar: a change from a people not fit to enter Israel, to a fit people
40 seah in the Mikvah: a change from a goy to a Jew, or from an assur woman to a mutar woman
40 lashes: from a sinner to a righteous
40 days of the mabul
40 days on Har Sinai
40 days from seed to embryo
there are more