Truth

John 14:9: "Jesus saith unto him, Have I been so long time with you, and yet hast thou not known me, Philip? he that hath seen me hath seen the Father; and how sayest thou then, Show us the Father?"
Believe me Jesus didn't make that statement smiling. He was disappointed. One can actually be with Jesus for donkey years without knowing Him.
Talking about the children of Israel:
Ps 103:7: "He made known his ways unto Moses, his acts unto the children of Israel."