- Solar paradox
- How to make sure you're on the right side of things when Malachi's prediction of a sun which will "burn like a furnace" comes to fruition
- Why we suffer an overeating epidemic today and how to resist it
“Behold, I set before you today a blessing and a curse.” (11:26)
How can two diametrically opposed actions originate from the same source?
The Kli Yakar notes that the emphasis on “day” (as in "today") represents the Sun, which produces two contrasting results using only one function:
The Sun, a single entity, produces 2 diametric effects.
It melts wax even as it hardens an egg.
It darkens the face of the person doing the laundry even as it whitens the laundry.
And these differences don’t come from the Sun, but from how the Sun is received.
And so it is with blessings and curses that originate from Hashem.
….
According to what we find in Chazal (Nedarim 8):
“There will be no Gehinnom in the World to Come. Rather, Hashem will remove the sun from its sheath, and the righteous will be healed by it, while the wicked will be punished by it, as it says (Malachi 3:19): “A sun will come which will burn like a furnace; all the wicked and all the evildoers will be like straw, and the sun will incinerate them....”
Moreover, the righteous will derive pleasure from the sun, as it says (Malachi 3:20): “And the sun of mercy shall rise with healing in its wings for you who fear My Name.”
Therefore it says “today a blessing and a curse,” in that both a blessing and a curse will be culled from the Sun.
....a good thought is as if one actually performed it, yet Hashem does not associate a bad thought with a deed.
Advice for Holy Eating
This teaches that a person doesn’t yearn after desires (taavot) except within an excess of expanse [harchavah yetirah].
But if he can’t eat them until he hunts them in a forest or he needs to hunt poultry in the wilderness where one faces danger, and must go to the great trouble of hunting, then his desires will be subdued because the eating isn’t worth the great stress and bother.

Furthermore, the Kli Yakar uses this opportunity to recommend that we eat meat only occasionally.
I found this particularly interesting in light of the overeating epidemic today.
The wide availability of even the finest foods (“an excess of expanse”) is apparently connected to the desire for eating.
I guess this explains why in the olden days, people didn’t have the same food issues we see today.
This is my own translation and any errors are also mine.