John 8:38

“I speak the things which I have seen with my Father, and you also do the things that you have heard from your father.”

Jesus now contrasted Himself with them enigmatically. He pointed out that He spoke only of what He had seen with His Father. Thus what He spoke was good and true. His abiding in the Father was constant and affected all that He said. But the Judaisers on the other hand spoke what they had heard from their father. The implication was that their father was less worthy. (Later he would show that this referred to the Devil, for it was he, not Abraham, whose ways they followed).

Note the distinction between ‘seen' and ‘heard'. Jesus was speaking of what He had actually seen and witnessed (compare John 3:11; John 3:32; John 14:7). They had only ‘heard'.