south ... south ... south - three different Hebrew words, to express the certainty of the divine displeasure resting on the region specified. The third term is from a root meaning “dry,” referring to the sun’s heat in the south; representing the burning judgments of God on the southern parts of Judea, of which Jerusalem was the capital.
set thy face - determinately. The prophets used to turn themselves towards those who were to be the subjects of their prophecies.
drop - as the rain, which flows in a continuous stream, sometimes gently (Deu 32:2), sometimes violently (Amo 7:16; Mic 2:6, Margin), as here.
forest - the densely populated country of Judea; trees representing people.