6.
The Discourse on Sleepiness and Lethargy
16.
"Sleepiness, lethargy, yawning, discontent, drowsiness after meals:
Because of this, the noble path does not shine forth here among beings."
[The Blessed One:] "Sleepiness, lethargy, yawning, discontent, drowsiness after meals:
When one dispels this with energy, the noble path is cleared."