Job 20:4

“Knowest thou [not] this of old, etc.] Or “from eternity” f772, from the beginning of time, ever since the world was; as if he should say, if you are the knowing man you pretend to be, you must know this I am about to observe; and if you do not know it, you must be an ignorant man, since it is an ancient truth, confirmed by all experience from the creation; not that Job could know it so early, he was not the first man that was born, nor was he made before the hills, but was of yesterday, and comparatively knew nothing; but the sense is, that this about to be delivered was an old established maxim, of which there had been numerous instances, since man, or “Adam”, was placed upon earth;…”

“Knowest thou not this of old - That is, dost thou not know that this has always happened from the beginning of the world, or that this is the invariable course of events. His purpose is to show that it was the settled arrangement of Providence that the wicked would be overtaken with signal calamity. It was “so” settled that Job ought not to be surprised that it had occurred in “his” case. Zophar goes on to show that though a wicked man might rise high in honor, and obtain great wealth, yet that the fall would certainly come, and he would sink to a depth of degradation corresponding to the former prosperity. Since man was placed upon earth - Since the creation; that is, it has always been so.…”

“This - Which I am now about to say. Since - Since the world was made. Job 20:6”

“thou not: Job 8:8, Job 8:9, Job 15:10, Job 32:7 man: Gen 1:28, Gen 9:1-3; Psa 115:16 Job 20:5”