Isa 40:21 Do you not know? Do you not hear? Has it not been told you from the beginning? Have you not understood from the foundations of the earth?
In Isaiah 40:20 the prophet chastises Israel for setting up idols “that will not move” over God. He then follows this statement with further condemnation. Israel has “from the foundations of the Earth” understood who the real creator is. The language mirrors that of omniscience. If a reader wants to take this in a wooden sense, the people have knowledge that at least dates to the creation of the world if not eternal knowledge.
But a natural reader of the text will read this as a generalization. God has made Himself apparent to Israel (and perhaps the world) since the world was created. The knowledge is new knowledge that is generated within people as they observe the world. It is old knowledge in the sense the information is out there to be “understood”.
This generalization, if applied to God, would certainly find itself in lists of omniscience prooftexts. Other “foundations of the Earth” prooftexts, such as 1 Peter 1:20, regularly make their way into such lists. But when such language is used of man, the text is naturally read and forgotten. The chance phrase, which would be critical in the context of God, is not even noticed.