We are but shadows

Job 8:9: “For we are but of yesterday, and know nothing...”
1 Chronicles 29:15: "For we are strangers before thee, and sojourners, as all our fathers were; our days upon earth are as a SHADOW, and there is no expectation. There is no reason to hope that we shall be prolonged; for our lives are limited down to threescore years and ten, as the average of the life even of old men.
The human life was extended to a much longer date than that in which Job lived; when men, from the long period of eight or nine hundred years, had the opportunity of making many observations, and treasuring up a vast fund of knowledge and experience. Are we ready to confess our ignorance for have we not repeated the same sins through out the years?
In comparison with them, we considers that age as nothing, and that generation as being only of yesterday, not having had opportunity of laying up knowledge: nor could we expect it, as our days upon earth would be but a shadow, compared with that substantial time in which the fathers had lived.
Blessed be G-d, now that we have the word of G-d in writing, and are directed to search. We need not enquire of the former age, nor prepare ourselves to the search of their fathers; for, though we ourselves are but of yesterday, the word of G-d in the Scripture is as nigh to us as it was to them (Rom. 10:8), and it is the more sure word of prophecy, to which we must take heed. If we study and keep G-d’s precepts, we may by them understand more than the ancients, Ps. 119:99, 100.
We do not live so long as those of the former age did, to make observations upon the methods of Divine Providence, and therefore cannot be such competent judges as they in a cause of this nature.
Perhaps there may be an allusion here to the shadow projected by the gnomon of a dial, during the time the sun is above the horizon. As is a single solar day, so is our life. "We are shadows!" referring to the different shadows by which the gnomon marked the hours, during the course of the day; and all intended to convey this moral lesson to the passengers:
Your life is composed of time, marked out by such shadows as these. Such as time is, such are you; as fleeting, as transitory, as unsubstantial. These shadows lost, time is lost; time lost, soul lost! Reader take heed!