John 5:37

But over and above the evidence of the works καὶ ὁ πέμψας με πατήρ, αὐτὸς μεμαρτύρηκε, “And the Father who sent me has Himself also testified”. Where and how this testimony of the Father's separate from the works has been given, is explained, John 5:38; John 5:40 But, first, Jesus states how it has no been given: οὔτε φωνὴν αὐτοῦ … ἑωράκατε. It is not by coming into your midst in a visible form and speaking as I speak that the Father has testified. “His voice you have never heard: His form you have never seen.” It is not by sensible sights and sounds the Father has given His testimony. [This interpretation is however ignored by most: by Meyer, who thinks the reference is to their insensibility to the revelation of God in Scripture; by Westcott, who says “the Jews by their disbelief of Christ failed to hear and see Him”; by Godet, who finds “a declaration of man's natural impotence to rise to the immediate and personal knowledge of God”. Reference to the baptism is put out of the question by πώποτε. The reference to the two chief forms of prophetic revelation (Weiss) is too remote.]