Job establishes a firm boundary with his companions, asserting his own authority and making it clear that they hold no advantage over him in understanding God’s ways in the world. Whatever they attempt to teach him regarding God's greatness and unlimited power is already deeply familiar to him.
Commentators explore exactly what Job refers to when he claims to know all of these things. The primary approach among commentators is that he is addressing everything his friends have just argued about divine providence and might [רמב״ן, ביאור שטיינזלץ]. Others suggest he is pointing back to the events he himself just described [מצודת דוד], while another view understands it as a broad declaration that he simply possesses a comprehensive knowledge of the world [חומת אנך].
To prove the truth of his understanding, Job relies on three distinct channels of perception: sight, hearing, and mental processing. First, he testifies that he has witnessed God's actions directly and tangibly, as His deeds are famous and visible to everyone [תקות אנוש]. This sight can also be understood as an internal vision, seen through the mind's eye [חומת אנך]. Hearing then joins sight to confirm it. By listening to the testimony of others regarding these events, Job verifies that his own eyes did not deceive him and that he is not suffering from an illusion [מלבי״ם, תקות אנוש]. Furthermore, hearing represents the reception of tradition and wisdom passed down from previous generations [רמב״ן].
Finally, Job engages in active mental processing. He does not merely collect data through his senses; he fully realizes that every event occurs strictly by the word of God [מצודת דוד]. This transforms his sensory input into a true, clear, and logical grasp of reality [מלבי״ם].
On a deeper level, this defense serves as a direct, systematic response to the specific debating methods used by his three friends. Eliphaz based his arguments on what he had seen with his own eyes, Bildad relied on what he had heard through tradition, and Zophar built his case on human logic and reason. Job meets each of them exactly where they stand. He counters Eliphaz with his own sight, Bildad with his own hearing, and Zophar with his own mental understanding. Through this, he proves that they have no reason to act superior, as he commands every single tool of perception that they do, all at once [אלשיך].