Quotes Uncovered: Time, Money, and Cake

A while back, I invited readers to submit quotations for which they wanted me to try to trace the origins, using The Yale Book of Quotations and more recent research by me. Hundreds of people have responded via comments or e-mails. I am responding as best I can, a few per week.

Marc Anthony asked:

“You can’t make your cake and eat it too,” refers to having everything work your way. Please research. This is a ridiculously clichéd quote. I made the cake. I will eat the cake.

The Yale Book of Quotations, which attempts to trace all famous quotations to their accurate origins, has the following:

At length I recollected the thoughtless saying of a great princess, who, on being informed that the country people had no bread, replied, “Then let them eat cake.” Jean-Jacques Rousseau, Confessions (1782).

The words “let them eat cake” are usually attributed to Marie-Antoinette, but the Rousseau usage, written in 1766 to 1767, before she had even arrived in France, makes it clear that the saying predated this famous queen.
David asked:

How about, “This too shall pass”?

The YBQ quotes Edward FitzGerald, Polonius: A Collection of Wise Saws and Modern Instances (1852):

The Sultan asked for a Signet motto, that should hold good for Adversity or Prospertiy. Solomon gave him, “This also shall pass away.”

Science Minded asked:

“Time is money” and “A penny saved is a penny earned.” The first two are Benjamin Franklin — I would imagine this last one is his too: “Haste makes waste.”

The first one is from Franklin, but not the others. Thomas Fuller, in The Worthies of England (1662) wrote “a penny saved is a penny gained.” John Heywood included “Haste makes waste” in Dialogue of Proverbs (1546).
Do any readers have any other quotations whose origins they would like me to attempt to trace?
Addendum: I did this week’s posting hastily and confused the two “cake” quotations. I’ll answer Marc Anthony’s actual question next week.