This is an icon of the “Hospitality of Abraham,” an Old Testament image which in the Orthodox tradition is a type of the Trinity. (The most famous version is the one painted by Andrei Rublev.) The figure in the middle is Christ, as you can tell from the inscription. How can you render as a “visual expression” the “inexpressible” nature of the Trinity? Icons allow one to incarnate spiritual mysteries in visible form, without reifying these images into literal truths. Moreover, they lead us towards the “dazzling darkness” which is not a place of emptiness but of the superessential fullness (“pleroma”) of the Godhead.
“The icon therefore does not lead us to the absence of images pure and simple. It leads rather above and beyond the image toward the indescribable Hyper-icon; this is its apophatic character, that is, iconographic apophaticism. The icon is the last arrow of human eros shot at the heart of the mystery.”
Paul Evdokimov, “The Art of the Icon,” 236.