15. Those whom I regarded as "my brethren," from whom I looked for faithfulness in my adversity, have disappointed me, as the streams failing from drought—wadies of Arabia, filled in the winter, but dry in the summer, which disappoint the caravans expecting to find water there. The fulness and noise of these temporary streams answer to the past large and loud professions of my friends; their dryness in summer, to the failure of the friendship when needed. The Arab proverb says of a treacherous friend, "I trust not in thy torrent" (Isa 58:11, Margin).

     16. blackish—literally, "Go as a mourner in black clothing" (Ps 34:14). A vivid and poetic image to picture the stream turbid and black with melted ice and snow, descending from the mountains into the valley. In the [second] clause, the snow dissolved is, in the poet's view, "hid" in the flood [UMBREIT].

     17. wax warm—rather, "At the time when." ("But they soon wax") [UMBREIT]. "they become narrower (flow in a narrower bed), they are silent (cease to flow noisily); in the heat (of the sun) they are consumed or vanish out of their place. First the stream flows more narrowly—then it becomes silent and still; at length every trace of water disappears by evaporation under the hot sun" [UMBREIT].