Bede

And the waters held sway over the earth for one hundred and fifty days. And this number pertains to the same mystery as the number fifteen because seventy is derived from seven, and eighty from eight; combining both numbers, the waters held sway over the earth for one hundred and fifty days, thus commending and confirming the sacrament of baptism in consecrating the new man towards upholding the faith in rest and resurrection.

Commentary on Genesis (Hexaemeron) ↗