The young men saw me, and hid themselves - That is, they retired as if awed at my presence. They gave place to me, or reverently withdrew as I passed along.
And the aged arose, and stood up - They not merely rose, but they continued to stand still until I had passed by. "This is a most elegant description, and exhibits most correctly the great reverence and respect which was paid, even by the old and the decrepit, to the holy man, in passing along the streets, or when he sat in public. They not only rose, which in men so old was a great mark of distinction, but they stood; and they continued to do it, though the attempt was so difficult." Lowth. The whole image presents a beautiful illustration of Oriental manners, and of the respect paid to a man of known excellence of character and distinction.

The young men saw me, and hid themselves - From all classes of persons I had the most marked respect. The Young, through modesty and bashfulness, shrunk back, and were afraid to meet the eye of their prince; and the Aged rose from their seats when I entered the place of judgment. These were the elders of the people, who also sat with the judge, and assisted in all legal cases.

The young men saw me, and (e) hid themselves: and the aged arose, [and] stood up.
(e) Being ashamed of their lightness and afraid of my gravity.

The young men saw me, and hid themselves,.... Through a veneration of him; which was much, since young men, through a vain conceit and opinion of themselves, are apt to treat their superiors in age with slight, neglect, and contempt; or through fear, lest he should spy them, and call them to him, and examine them closely concerning their conduct and behaviour, and reprove them for their youthful follies he might have knowledge of:
and the aged arose and stood up; as he passed by them, to show their respect unto him; or when he came into court, they rose up, and continued standing until he had took his seat; and even then kept the same posture, attending to his counsel and instruction, to his definitive sentence and decision of matters in debate; though they were venerable persons themselves, and such as before whom young men were to arise, Leviticus 19:32; and were also men of wisdom and prudence, Job 12:12; yet these men rose and stood up, paying a deference to Job's superior sense and judgment.

hid--not literally; rather, "stepped backwards," reverentially. The aged, who were already seated, arose and remained standing (Hebrew) until Job seated himself. Oriental manners.

When Job came hither to the meeting of the tribunal, or the council of the elders of the city, within which he had a seat and a voice, the young men hid themselves, conscious of his presence (which εἰρομένῃ λέξει, or, is expressed paratactically instead of as a period), i.e., they retired into the background, since they feared his look of salutation;
(Note: Comp. jer. Schekalim ii. 5 (in Pinner's Compendium des Thalmud, S. 58): "R. Jochanan was walking and leaning upon R. Chija bar-Abba, R. Eliezer perceived him and hid himself from him (ומטמר לח מקמי). Then said R. Jochanan: This Babylonian insulted him (R. Chija) by two things; first that he did not salute him, and then that he hid himself. But R. Jakob bar-Idi answered him, it is the custom with them for the less not to salute the greater, - a custom which confirms Job's words: Young men saw me and his themselves.")
and old men (hoary heads) stood up, remained standing (ἀσυνδέτως, as Job 20:19; Job 28:4). קוּם signifies to stand up, עמד to advance towards any one and remain standing. They rose in order not to seat themselves until he was seated. שׂרים are magnates (proceres) of the city. These עצרוּ בּמלּים, cohibebant verba (עצר with Beth of the obj., as Job 4:2; Job 12:15), and keeping a respectful silence, they laid their hand on their mouth (comp. Job 21:5). All stepped back and desisted from speaking before him: The speech of illustrious men (נגידים from נגד, Arab. njd, to be visible, pleasant to the sight, comp. supra, p. 510) hid itself (not daring to be heard), and the tongue of the same clave (motionless) to their palate. We do not translate: as to the voice illustrious men hid themselves, for it is only the appearance produced by the attractional construction Ges. 148, 1 that has led to the rendering of קול־נגידים as an acc. of closer definition (Schult., Hahn: quod ad vocem eminentium, comprimebantur). The verb is construed with the second member of the genitival expression instead of with the first, as with מספר, Job 15:20; Job 21:21; Job 38:21, and with ראשׁ, Job 22:12; a construction which occurs with קול not merely in such exclamatory sentences as Genesis 4:10; Isaiah 52:8, but also under other conditions, 1-Kings 1:41, comp. Job 14:6. This may be best called an attraction of the predicate by the second member of the compound subject, like the reverse instance, Isaiah 2:11; and it is sometimes found even where this second member is not logically the more important. Thus Ew. transl.: "the voice of the nobles hides itself;" whereas Olsh., wrongly denying that the partt. in passages like Genesis 4:10; 1-Kings 1:41, are to be taken as predicative, wishes to read נחבא, which is the more inadmissible, as even the choice of the verb is determined by the attractional construction.
The strophe which follows tells how it came to pass that those in authority among the citizens submitted to him, and that on all sides the people were zealous to show him tokens of respect.