Musar zu Mischlej 24:33

Behold, Shlomo repeatedly exhorted many times on this in seeing the evil of laziness and the greatness of the harm resulting from it. He said "a little sleep, a little slumber, a little folding of the hands to rest. Then shall your poverty come as a traveler" (Mishlei 24:33). For behold, even though the lazy person is not doing evil actively, nevertheless he brings evil on himself through his very inactivity.