I smiled on them when they had no confidence, and the light of my face they did not cast down.
That which crowned Job's prosperity was the pleasing prospect he had of the continuance of it. Though he knew, in general, that he was liable to trouble, and therefore was not secure (Job 3:26, I was not in safety, neither had I rest), yet he had no particular occasion for fear, but as much reason as ever any man had to count upon the lengthening out of his tranquility. I.
Commenting on Job 29:18-25
If I laughed on them, they believed it not,.... Not that he at any time laughed at them, by way of derision; but when in a cheerful frame of mind, or in a merry mood, he used freedom and familiarity, and jested with them; but they could not believe that he did jest, or was in jest, he being a man always of such gravity...
When I relaxed from my wonted gravity (a virtue much esteemed in the East) and smiled, they could hardly credit it; and yet, notwithstanding my condescension, they did not cast aside reverence for my gravity. But the parallelism is better in UMBREIT'S translation, "I smiled kindly on those who trusted not," that is, in times of danger I cheered those in despondency.