For inquire, I pray thee, of the former age, and prepare thyself to the search of their fathers:
The former age - the age immediately preceding Job.
Their fathers - the fathers pricking that age, and therefore still further back. The sages of the olden time reached an age beyond those of Job's time (see the note at Job 42:16); and therefore could give the testimony of a fuller experience.
Of yesterday - i:e., a recent race. We know nothing as compared with them, from the brevity of our lives. So even Jacob - "Few and evil have the days of the years of my life been, and have not attained unto the days of the years of the life of my fathers in the days of their pilgrimage" (Genesis 47:9). Knowledge consisted then in the results of observation embodied in poetical proverbs, and handed down by tradition. Longevity gave the opportunity of wider observartion.
A shadow. "Man is like to vanity: his days are as a shadow that passeth away" (Psalms 144:4); "We are strangers before thee, and sojourners, as were all our fathers: our days on the earth are as a shadow, and there is none abiding" (1 Chronicles 29:15).