Aaron was the brother of Moses. He symbolizes two things, at different stages of the story.

During the first part of the exodus, when he was Moses' spokesperson, Moses represents the Word as it truly is, as it is understood in heaven, while Aaron represents the Word in its external sense, as it is understood by people in the world. This is why Aaron talks for Moses, and the Lord says of him "he shall be as a mouth for you, and you shall be to him as God." (Exodus 4:16)

Later, after the Tabernacle was built and he was inaugurated as high priest (see Leviticus 8,9), Aaron represents the Lord as to the Divine Good, and Moses represents the Lord as to the Divine Truth.

In Exodus 28:1, Aaron signifies the conjunction of Divine Good with Divine Truth in the Divine Human of the Lord. (Arcana Coelestia 9806, 9936)

In Exodus 32:1, Aaron represents the external of the Word, of the church, and of worship, separate from the internal. (Arcana Coelestia 10397)

In Exodus 4:14, before he was initiated into the priesthood, Aaron represents the doctrine of good and truth. (Arcana Coelestia 6998)

6849. 'For he was afraid to look at God' means for fear that they should suffer harm from the presence of the Divine itself. This is clear from the meaning of 'being afraid' as for fear that they, interior things, should suffer harm (for this was the reason for his fear); and from the meaning of 'looking at God' as the presence of the Divine itself. For the only way in which the Lord can make Himself present before a person is through the persons inner seeing, through seeing Him with the eye of faith that belongs to charity. If the Lord does manifest Himself in an outward visible form to someone, it is still the inner levels of mind that are affected, for the Divine reaches into the deepest parts of him. With regard to the meaning here, that interior things should not suffer harm from the presence of the Divine itself, and that therefore they were to be protected, the situation is this: The Divine itself is pure love, and pure love is like a fire hotter than the fire of the sun in this world. Consequently if Divine Love in its purity were to flow into any angel, spirit, or man, he would be completely destroyed, which is why so many times in the Word Jehovah or the Lord is called a consuming fire. To ensure therefore that the angels in heaven suffer no harm from the flow of heat from the Lord as the sun, each of them is veiled with a kind of thin cloud suited to the individual, which moderates the heat flowing in from that sun.

[2] The truth that without this form of preservation everyone would be destroyed by the presence of the Divine had been well known to the ancients, which was why they were afraid of seeing God, as is clear in the Book of Judges,

Gideon saw that he was the angel of Jehovah, therefore Gideon said, O Lord Jehovah! Inasmuch as I have seen the angel of Jehovah face to face. And Jehovah said to him, Peace be to you; do not fear, for you will not die. Judges 6:12, 23.

In the same book,

Manoah said to his wife, We shall surely die, for we have seen God. Judges 13:22.

And in the Book of Exodus,

Jehovah said to Moses, You cannot see My face, for no man will see My face and live. Exodus 33:20.

[3] When therefore Moses was allowed to see God, he was placed in a cleft of the rock, Exodus 33:22, which represented the dimness of his faith, and the clouds that hid and protected him. How dangerous it can be for angels to be beheld by the Divine without being covered by a cloud is made very clear by the fact that when angels look at any spirit who is governed by evil he seems to change into something resembling a lifeless object, as I have often been allowed to see. The reason why this happens is that when the angels look at someone there is cast in his direction the light and heat of heaven, and the truth of faith and the good of love with them, which - when these penetrate - virtually deprive the evil of life.

[4] If this is what happens when angels look at them, what would happen if the Lord did so? This explains why the hells are utterly remote from heaven, and why those who are there wish to be remote, for if they are not they suffer dreadful torment. This makes plain the meaning of the following words, They will say to the mountains and rocks, Rush down on us and hide us from the face of Him who is seated on the throne. Revelation 6:16; Luke 23:30; Hosea 10:8.

[5] Thus the presence of the Divine itself is such that no angel can bear it unless he is protected by a cloud which tempers and moderates the rays of light and the heat from that sun. From this one may recognize plainly that the Lord's Human is Divine, for if it were not Divine it could never have become so united to the Divine itself, called the Father, that they are one, according to the Lord's words in John 14:10 and following verses, and elsewhere. For that which is to receive the Divine in this way must be wholly Divine; what was not Divine from such a union would be plainly reduced to nothing. Let me use a comparison. Can anything be thrown into the fire of the sun and not be destroyed, unless it is similar in nature to the sun? So, can anyone enter the intense heat of infinite love unless he has in him the heat of the same kind of love, consequently unless he is none other than the Lord? The truth that the Father is within Him and that the Father does not show Himself except within His Divine Human is clear from the Lord's words in John,

Nobody has ever seen God; the only begotten Son who is in the bosom of the Father, He has made Him known. John 1:18.

And elsewhere in the same gospel,

You have never heard His voice nor seen His shape. John 5:37.