John Gill Commentary John 8:27

"They perceived not that he spake to them of the Father." — John 8:27 (ASV)

They understood not that he spoke to them of the Father. That sent him, and who was true and faithful to all he has said, whether in a way of promise, or threatening.

Such was their stupidity, that they did not know that he meant God the Father by him that sent him, so deriving his mission and doctrine from him.

Their hearts were made fat, and hardened, and their eyes were blinded. The Vulgate Latin version reads, "they did not know that he said, God was his Father"; and so Beza's most ancient copy, and another exemplar of his.