The real version of the quote is actually "Thou, O God, dost sell us all good things at the price of labor." by Leonardo da Vinci
Meaning:
"Leonardo da Vinci knew that God helps those who help themselves and that this could be hard work. The labor that brings us all good things is more than just our effort in the outer world — it is a reflection of our inner work and ethical awareness. Thus the prayer"
"According to Leonardo da Vinci we must be willing to work for the things we need or want in life. This quote may also be interpreted as a reminder that nothing in life comes easily, and that we must be willing to put in the time and effort to achieve the things we desire."
- online sources
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Most of us, myself included, probably started to know De Vinci from his famous paintings of "Mona Lisa" (actually if you go to the louvre and see some other paintings by De Vinci, you can see that mysterious smile everywhere ;-) and "The Last Supper". Only later on, I learned that he had also studied science and engineering among many other things, and recorded these studies in 13,000 pages of notes and drawings - called "The Notebook", in which today's APAD came from.
I feel this APAD fitting for the Labour Day weekend celebration, even people may just treat it as a regular long weekend.
So my friends, wherever you are and whatever you do for this long weekend (hopefully it's not work), you earned and deserve it !!! 
