If you ever wondered where guidance comes from, here is a great example, from about 10 minutes ago.
In an email conversation, one of my "interns" was commiserating with me... because the refrigerator died again, and this time there is no excuse: it needs to be replaced.
But... in order to bring in a new one, I have to push stuff aside, clean the old one from now rotting stuff... and I feel very weak to even contemplate doing it.
So she says (my intern): "and everything feels heavy when you're weak."
Lucky formulation of a sentence... because it woke me up. This, what she says, is true across the board. It is true in the physical realm, and it is even more true in the "psychological" realm: if you feel weak you'll do little.