I read this in Moll Flanders:
...I took care to lay up as much money as I could for a wet day...
and went looking for the origin of the idiom "to save for a rainy day". I found it was from a play, The Bugbears, by John Jeffere/Jefferay/Jefferie (they can't agree on the spelling) but couldn't find how it was actually used. Here it is:
wold he have me kepe nothyng agaynst a raynye day?
Would he have me keep nothing against a rainy day?
You have got to love the spelling. My thanks to Google book search. Link to text (see page 26)