5199. 'Beautiful in appearance' means which are expressions of faith. This is clear from the meaning of 'beauty' and 'appearance'. Spiritual 'beauty' is essentially an affection for interior truth, while spiritual 'appearance' is essentially faith, so that 'beautiful in appearance' means an affection for the truth of faith, see 553, 3080, 3821, 4985. The reason spiritual beauty is an affection for interior truth is that truth is the outward form taken by good. The good which they receive in heaven from the Divine provides angels with the life they possess; but the outward form taken by that life is provided by the truths springing from that good. The truth of faith however does not provide the beauty but the affection itself present within the truths of faith springing from good. Beauty that is provided solely by the truth of faith is like the beauty of a face seen in a painting or a sculpture, but the beauty provided by an affection for truth springing from good is like the beauty of a real face full of life imparted to it by heavenly love; for as is the love - that is, as is the affection - which shines out of the form provided by the face, so is the beauty seen there. This being so, the outward appearance of the angels is indescribably beautiful. Their faces are radiant with the good of love passing through the truth of faith, which good and truth not only present themselves visually but can also be felt from the spheres that emanate from them.
[2] The reason why this is the source of beauty is that heaven in its entirety is the Grand Man and has a correspondence with every single part of the human being. Everyone therefore who has the good of love and for that reason the truth of faith present in him has the form which heaven possesses present within him; and as a consequence of this there is also imparted to him the beauty which heaven possesses, heaven being a place where the Divine going forth from the Lord is the All in all. This also explains why those in hell, being the opposite of what is good and true, are horribly ugly, and in the light of heaven do not look like human beings but like monsters. The reason why spiritual appearance (aspectus) is faith is that in the internal sense 'looking at (aspicere) and seeing' means understanding, and in a sense more internal than this having faith is meant, see 897, 2150, 2315, 2807, 3863, 3869, 4403-4421.