Adam Clarke on John 14:8

Show us the Father - As if he had said, We have seen and adored thee, and our happiness will be complete if thou show us the Father. The demand of Philip was similar to that made by Moses, Exo 33:18. He wished to see the glory of God. In Peter, James, or John, this would have been inexcusable; but Philip had not seen the transfiguration on the mount. The Jewish history is full of the manifestations which God made of himself, and especially when he gave the law. As Christ was introducing a new law, Philip wished to have an additional manifestation of God.