Gian Carlo Menotti says "Amahl and the Night Visitors" is "an opera for children because it tries to recapture my own childhood. You see, when I was a child I lived in Italy, and in Italy we have no Santa Claus. I suppose that Santa Claus is much too busy with American children to be able to handle Italian children as well. Our gifts were brought to us by the Three Kings, instead."

When Menotti was 40, he repaid those Three Kings of his childhood in the best way he could: He wrote beautitful music for them to sing in an opera that has, in less than 30 years, become one of the classics of the Christmas season.

It wasn't easy for Menotti. Because, you see, he had forgotten about the kings. "In 1951," he tells the story, "I found myself in serious difficulty. I had been commissioned by the National Broadcasting Company to write an opera for television, with Christmas as a deadline, and I simply didn't have an idea in my head."

But the Three Kings whom Menotti had forgotten-"the big Christmas tree in Rockefeller Plaza, the elaborate toy windows on Fifth Avenue, the 100-vocie choir in Grand CentralStation, the innumerable Christmas carols on radio and television- all these things made me forget the three dear old kings of my childhood," he said-came back to to him when he needed them.

"One November afternoon as I was walkingrather gloomily through the rooms of the Metropolitan Museum, I chanced to stop in front of the Adoration of the Kings by Hieronymous Bosch, and as I was looking at it, suddenly I heard again, coming from the distant blue hills, the weird song of the Three Kings. I then realized they had come back to me and had brought me a gift."

Once the kings returned to him, Menotti had no trouble giving NBC its opera. It was seen and heard weeks later, on Christmas night, when it made instant, lifelong friends, of Kaspar, Melchior and Balthazar, for many who may not have known them well until that night.

Most of all, however, it brought into the hearts of all who saw the opera a young boy named Amahl-"a crippled boy of about 12." There is an autobiographical touch here, since Menotti himself was lame for a time as a child.

The kings were Menotti's old friends."My favorite was Melchior," he says," because he was the oldest and had a long white beard. My brother's favorite was King Kaspar. He insisted that this king was a little crazy and quite deaf. I don't know why he was so positive about his being deaf. I suspect it was because dear KingKaspar never brought him all the gifts herequested."

Kaspar may also become the favorite of thousands who tonight see "Amahl" for the first time. Because Kaspar gets to sing a song that is popular with "Amahl" lovers: "This is my box, this is my box-I nveer travel without my box." And what is in that box? "Licorice!" cries Kaspar, "Sweet, black licorice!"

The instant success of "Amahl" raises the questions; What makes a classic? When does a new work become one? Handel's "Messiah" was performed 42 or 43 times during his lifetime, often over strong clerical protest and never in church. It was not until a generation or more after Hanel's death in 1759 that "Messiah" attained the status it has retained ever since: The most frequently performed (at least in part), aside from several favorite carols, of all musical works at Christmas. Now in its 27th year, "Amahl" has for some years followed immediately after.

What is it about this singular work, which lasts a total of around 46 minutes, that places it in that rare company of "Messiah," "Twas the Night Before Christmas" and Dickens' A Christmas Carol?"

Its story is the height of simplicity: A little crippled boy lives with his poor, widowed mother. They are cold and hungry in their small, empty house. Three kings, on their way to Bethlehem, stop at the house and ask for shelter for the night. Amahl and his mother, who apologizes for their proverty, welcome the kings and call in their shepherd neighbors to bring food and dance for the regal visitors. Amahl's mother is astounded by the kings' splendid robes and the rich gifts which they say they are carrying to a newly born baby. Jealous of the new child, and worried for her own crippled son, Amahl's mother steals a bit of the gold, only to be caught in the act. The kings, understanding her fears, tell her to keep the gold, explaining that the child they are seeking will not need it.

As she hears more about the new baby, the mother wishes she had something to send as a gift. It is at this point that Menotti captures the hears of millions who have come to know and love his opera. Amahl offers the kings the dearest thing he has left, his wooden crutch.

There is a moment of silent astonishment as the crippled boy gives his crutch to the kings. Then his mother speaks softly."He walks!" is all she can murmur, and each king repeats after her, "He walks! He walks! He walks!" Suddenly the wonder of the marvelous thing that has happened strikes them all. While his mother and the kings watch in delighted amazement. Amahl runs a little as he sings, "Look mother, I can dance I can jump, I can run!" Menotti has shown us a miracle.

People often ask, "What is the best opera with which to introduce children to opera?" I should think "Amahl." Its music is beautifully melodic. There are solos for Amahl and his mother, a trio for the kings, a chorus of the neighboring shepherds, some of whom dance.There is suspense, when Amahl's mother, in her big scene, moves slowly to steal the gold. There is even more and unexpected suspense at the moment Amahl throws away his crutch and starts to walk.

There is the glamor of the richly dressed kings, the exotic touches of their array, the gifts, an elegant Page and a parrot. And there is, for children of any age, a real, believable miracle.

All this comes to your television screen at 7 p.m. this evening in the newest TV production of "Amahl." Menotti, who is one of the world's great stage directors of his own or anyone else's operas, has put together for NBCI-TV a wonderfully warm, new "Amahl." It was filmed in Israel's Judaean hills, in predominantly warm shades of brown and yellow*.

Amahl's house, which has to be large enough to accommodate the shepherds and three dancers, is bare of any scrap of food or firewood. Robert Sapolsky is a touching, immensely friendly Amahl whose delighted interest in the kingly visitors is totally credible. His singing is matched by Teresa Stratas's as his mother. She looks more harrassed than other mothers have, and, perhaps because of that, sounds more petulant.

But her singing is right in tone in all her changing moods. The kings ar Giorgio Tozzi as Melchior, Nico Castel as Kaspar, and Willard White as Balthazar, with Michael Lewis a fine Page. There are moments of special magic: the first glimpse of the three kings at Amahl's door; the dancers, two men and one woman; the chorus as it leaves merely tops. Most of all there is that magical moment when Amahl holds his crutch out toward the kings and in that moment realizes that he is walking without its help.

Jesus Lopez-Cobos is conductor of the London Philharmonic, with the Ambrosian Opera Chorus making glorious sounds. It is a pity that this brief opera has to be interrupted twice for commercial breaks. A more sensitive sponsor would offer it at Christmas without interruption.