Surely you know, for you were already born! And the number of your days is great!
The Lord here proceeds to ask Job many puzzling questions, to convince him of his ignorance, and so to shame him for his folly in prescribing to God. If we will but try ourselves with such interrogatories as these, we shall soon be brought to own that what we know is nothing in comparison with what we know not.
Commenting on Job 38:12-24
Knowest thou it, because thou wast then born?.... When light and darkness were first separated, and had their several apartments assigned them; their laws and rules given them, and their bounds and limits set them? No; he was not: and, had he been the first man, could not have been early enough to have been present at the doing of this, and so come at...
Or without the interrogation, in an ironical sense [UMBREIT]. then--when I created light and darkness (Job 15:7).