Albert Barnes Commentary Job 29:4

"As I was in the ripeness of my days, When the friendship of God was upon my tent;" — Job 29:4 (ASV)

As I was in the days of my youth - The word here translated “youth” (חרף chôreph), properly means “autumn”—from (חרף châraph), to “pluck” or “pull,” as being the time when fruits are gathered. Then it means that which is mature; and the meaning here is probably “mature” or “manly”—“As I was in the days of my ripeness;” that is, of my vigor or strength. The whole passage shows that it does not mean “youth,” for he goes on to describe the honor and respect shown to him when in mature life.

So the Septuagint translates it—Ὅτε ἤμην ἐπιβρίθων ὁδούς (Hote ēmēn epibrithōn hodous)—“When I made heavy or laded my ways,” an expression referring to autumn as being laden with fruit. Similarly, we speak of the spring, the autumn, and the winter of life, and by the autumn denote the maturity of vigor, experience, and wisdom. The Greeks also used the word ὀπώρα (opōra)—Pindar, Isthm. 2, 7, 8; (Nehemiah 5:10); Aeschylus, Suppl. 1005, 1022.

So Ovid:

Excessit Autumnus posito fervore juventae
Maturus, mitisque inter juvenemque senemque;
Temperie medius, sparsis per tempora canis.
Inde senilis hiems tremulo venit horrida passu.
Aut spoliata suos, aut, quos habet, alba capillos.
Metam. 15.200.

The wish of Job was that he might be restored to the vigor of mature life, and to the influence and honors which he had then; or rather, perhaps, it was that they might have a view of what he was then, that they might see from what a height he had fallen, and what cause he had of complaint and grief.

When the secret of God was upon my tabernacle - The meaning of this language is not clear, and considerable variety has occurred in its interpretation. The Septuagint translates it, “When God watched over—ἐπισκοπὴν ἐποιεῖτο (episkopēn epoieito)—my house.” The Vulgate has, “When God was secretly in my tabernacle.” Noyes translates it, “When God was the friend of my tent.” Coverdale renders the whole, “As I stood when I was wealthy and had enough; when God prospered my house.” Umbreit translates, “Als noch traulich Gott in meinem Zette weilte”—that is, “When God remained cordially in my tent.” Herder offers, “When God took counsel with me in my tent.”

The word translated “secret” (סוד sôd) means a “couch” or “cushion” on which one reclines, and then a divan, or circle of friends sitting together in consultation (see the word explained in the notes at Job 15:8). The idea here probably is that God came into his tent or dwelling as a friend, and that Job was, as it were, admitted to the secrecy of his friendship and to an acquaintance with his plans.