Musar zu Jeschijahu 50:7

Even though most kings' occupation and speech is in matters of grand accomplishments and pleasures and David who was also a king, would seem to be embarrassed to speak words of Torah and ethics while in their company instead of great feats and pleasures like them. Nevertheless, he did not care at all. His heart was not enticed for these vanities after he had already attained the truth. Rather, he states explicitly: "I will speak of Your testimonies before kings, and will not be ashamed". Likewise Isaiah says: "I have set My face like a flint, and I know that I shall not be ashamed" (Isaiah 50:7).

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.

"nettles had covered the face of it" - since he did not labor sufficiently in the Torah, he sits in judgment and declares the pure, unclean and the impure, clean, thus breaching the fence set up by the Torah Sages. What is his punishment? Shlomo revealed it: "one who breaches a fence will be bitten by a snake" (Kohelet 10:8).