Divine sight is a non-apperceptible mental revelation. Divine revelation is an emotion of the mind by spiritual understanding, concerning the divine being. It is not even a faculty of the nature of the angels to be stirred into emotion at will, without a revelation granted by (divine) grace. Emotion by revelations concerning God’s activity is different from emotion by revelations concerning the nature of His being. The former is of a nature to have analogy with apperceptible things. The latter has absolutely no analogy with the intellect or anything. It is threefold purity as to its parts and its nature, as it is said. And it is impossible that one of the thousand righteous should be deemed worthy of this high apperception. Also speculation concerning the incarnation of our Lord and His revelation in the flesh is said to belong to divine speculation.
The true sight of the angels is emotion by spiritual understanding concerning their domain. But it is impossible for us to see the nature of spiritual forces without the mind.
When man is deemed worthy of seeing them in their nature and in their place and as they are in their spiritual creation, grace moves his mind by the revelation of spiritual insight concerning them. When the soul has been purified and is worthy of seeing its fellows, their sight is perceived with these eyes. They are not objects and they cannot be seen as they are, without alteration, but by psychic sight which is true contemplation. This means: without deterioration of their nature by sight. This sight cannot be acquired by any man without the second purification of the mind.
But the fact that the angels appear unto some men in images, is not due to true sight; but the angels minister unto the order of government by their mission. Or they show themselves for the consolation and encouragement of the simple, (in forms) perceptible by sight.
Such visions even happen to those who are not pure. But the first kind happens to illuminated and initiated people, who, by the glorious course of solitude, have been elevated unto the rank of purity.