Q. Why were the flies created which live only one day?
Reply. For the sake of the fly which in the future will torture Titus the wicked, and also for the sake of the fledglings of the raven. When they are hatched they are white and the parents fly away and leave them. Then they cry to God, as it is written, "The young of the raven which cry unto Him and He brings to them these flies and they are fed thereby." After three days they become dark; then the parents return to them. Thus the Lord, blessed be He, prepares the cure before the illness (f. 24a).