Bede

No one has ever seen God. A greater discussion is needed, since the Lord promises that the pure in heart will see God, and He says of the saints that their angels always see the face of the Father in heaven. John also stated this in his Gospel, where he consequentially adds how God can be seen, saying: The only begotten Son, who is in the bosom of the Father, He has declared Him (John I). Blessed Father Ambrose explained it thus: "And no one has ever seen God, because the fullness of the divinity dwelling in God has been seen by no one, comprehended by neither mind nor eyes. For 'seeing' must be referred to both. Hence when it is added: The only begotten Son, who is in the bosom of the Father, He has declared Him, it is a vision of the mind rather than of the eyes being spoken of. The form is seen, the power is narrated. The former is comprehended by eyes, the latter by the mind." Likewise, blessed Augustine in his book on seeing God, discussing the same question: "Therefore (he says), with the only begotten, who is in the bosom of the Father, narrating with ineffable narration, a rational, pure, and holy creature is filled with the ineffable vision of God. We will achieve this when we have become equal to the angels, for we shall see face to face (I Cor. XIII). As visible things are seen by the senses of the body, no one has ever seen God: because if He was ever seen in any way, it was not as a natural object is seen, but He willed to be seen in the form He chose, with His nature remaining hidden and unchangeable in Himself. But in the way He is seen as He is (I Cor. XIII), perhaps He is now seen by some of His holy angels. But by us, He will be seen in that way when we shall have become equal to them." And after some propositions, expounding the sentence of Saint Ambrose, Augustine says, "No one has ever seen God, either in this life as He is, or even in the life of angels, as these visible things are perceived by bodily vision, because the only begotten Son who is in the bosom of the Father, He has declared Him. Therefore, it pertains not to the vision of bodily eyes, but to the vision of minds." And after these many words: "To that vision (he says) by which we will see God as He is (I Cor. XIII), He admonished pure hearts. Because, indeed, bodies are by customary speech called visible, thus God is called invisible so that He may not be believed to be a body. It does not mean that He would deprive pure hearts of the contemplation of His substance, since this great and highest reward is promised to those who honor and love God, as the Lord Himself said when He visibly appeared to bodily eyes, and He promised to show Himself invisibly to pure hearts: Whoever loves me will be loved by my Father, and I will love him and show myself to him (John XIV). For His nature is equally invisible with the Father, just as it is equally incorruptible. Paul listed these consecutively, saying: Now to the King eternal, immortal, invisible, he commended the divine substance in a manner he could to humans through preaching. Therefore, God is an invisible reality, to be sought not with the eye but the mind. But just as if we wanted to see the sun, we would purify the eye of the body from which light can be seen; so also, wanting to see God, let us purify the eye of the heart with which God can be seen: Blessed are the pure in heart, for they shall see God (Matthew V). But since this vision is hoped for in the future, what must we do now, while still in the body, wandering away from the Lord? What solace should we use when divine vision is not yet permitted to us?"