‘Jesus says to him, “Have I been with you all (plural) so long and yet you (singular) do not know me, Philip? He who has seen me has seen the Father. How then can you say ‘show us the Father'? Do you not believe that I am in the Father and the Father in me? The words that I say to you I do not speak from myself. But the Father, dwelling in me, carries out his works”.'
Jesus corrects his false impression, and in doing so makes clear that to have seen Him is genuinely to have seen God. He points out that He is not just talking about them gaining a general impression of the Father from Him, but that they have actually seen the Father at work because the Father and Jesus are one in essence and being. That was why to have seen Him at work was to have actually seen the Father at work. It was taking the disciples a long time to recognise the truth before their eyes, and we should not be surprised. They have thought of Him as ‘Teacher and Lord', the great prophet and teacher, the supreme man of God, even the Messiah, although in a puzzling way. But the full truth had not yet dawned, and now they were faced with it with all the covers taken off. No wonder it was taking them time to grasp it.
And yet, like us, they should have known. Philip is rightly rebuked, even though gently, as the use of the singular reveals. Jesus is disappointed. He has been speaking God's own actual words, He has been revealing God through His life, and has been revealing the uniqueness of His relationship with the Father to such an extent that the Father is being seen at work in Him. Have they not seen His life? Have they not listened to what He has said? Who else could have done the works that He has done but God Himself? These works were clearly uniquely the work of God. (This does not just refer to the miracles, wonderful though they were, but to the whole of what He has done and been). Let them recognise that God has plainly walked on earth, revealed in a human body, ‘God openly revealed in the flesh' (1 Timothy 3:16). For ‘in Him dwells all the fullness of the Godhead in bodily form' (Colossians 2:9). And Philip really ought to have seen, and known.
Of course it is true that the Father is Spirit (John 4:24). Thus He cannot be literally seen in any bodily way either now or in the future. He is rather manifested through activity and truth. And it His activity and truth that has been revealed through Jesus to its fullest degree, so that every act of Jesus was the act of the Father. Thus He has actually manifested Himself through His Son. Jesus is saying that He IS a full manifestation of the Father, for they are One (John 10:30).
Notice Jesus' whole point here. He is answering a question in which the questioner wanted actually to literally SEE the Father, and He tells him that he has actually done so, not as a veiled reflection, but in actual fact. If Jesus had merely been saying that something of what the Father was could be seen in Him (something which can be said of many Christians) his rebuke to Philip would have been unjustified. For Philip's point was precisely that they were not wanting just some reflection of the Father, but an actual sight of the Father. And Jesus is saying that if Philip had really come to know Him he would have recognised that that is precisely what he had had.