An art of utmost purity

''Fra Angelico was an angel, I am but a man.'' How well one sympathizes with Guiseppe Molteni's sense of inadequacy. The famous restorer and Keeper of Milan's Brera Gallery had just been asked by Sir Charles Eastlake, the first Director of London's National Gallery, to retouch a painting by Fra Angelico. That was in 1858. Ever since, men have boasted of their inadequacy.

Since the nineteenth century, with the revival of interest in early Renaissance painting, Fra Angelico has been the object of legend that borders on cult. There are many - and I number among them - who if asked to live with but one artist's work, would choose Fra Angelico. His allure, now as in his own century, is his inimitability. No artist, one feels, has infused his subject matter with a more potent sweetness than this early master.

It's this very quality, indicative of some inner temperament, that garnered him his namesake: the angelic friar. Indeed, his work shines with a startling innocence. His namesake, of course, also stems from his favorite subject: bands of angels, coin-perfect in profile. They crowd his compositions. Even his saints and soldiers are, somehow, angels in disguise.

Their charm, in part, is their perfected scale. To appreciate Fra Angelico, one needs to study his surfaces with a magnifying glass. No larger than a thumbnail, his angel's faces are nonetheless perfectly rendered. So, too, the miniature details: hands and halos. Fra Angelico's genius for exquisitely miniaturized scenes owes much to his early training as an illustrator of illuminated manuscripts. His affinity for the finite, though, runs deeper. Like Blake, Fra Angelico found infinity in the small, the universe in a single face. And that face, radiant with quiet love, is always the same. It's this spiritual coherence that has drawn generations to his work.

History has exaggerated the link between Fra Angelico's vocations as friar and artist. Yet, undeniably, a link exists. With the exception of Giotto, one feels, Fra Angelico's work is unique in its genuine animation by faith. Just as simplicity of form hallmarks his style, so, too, it belies the feel of his work. The overriding quality of his work is purity. And it's this that makes restoring a Fra Angelico painting so difficult.

While most famous for his altarpieces and fresco cycle that decorate the cells at San Marco, the Florentine monastery where he lived between 1437-38, Fra Angelico's best loved work is his series of narrative scenes executed around 1451. ''The Flight Into Egypt,'' pictured here, is a fine example of that narrative style.

The panel, originally part of a series that decorated the doors of a silver chest in the church of the Santissima Annunziata in Florence, fuses the monumental with the lyrical. Here, Mary and Joseph flee into Egypt after the infant birth. Yet the scene is utterly serene. What Fra Angelico has captured is the surety, the unhurried trust of his figures. This tranquility, in turn, is imparted to the viewer. In his visual parable about guidance, Fra Angelico gently invokes the qualities of stillness and surety that are our real guides. In his small figures reside the small inner voice within us all.