It happens in front of your ears and eyes: a great work comes rolling off the stage. The Metropolitan Opera's production of Schoenberg's "Moses und Aron" was glorious when it was first presented, in February. It is now overwhelming.

Here is one moment, among many. Moses is off up the mountain, receiving the Ten Commandments. The Jews who have followed him are anxious and angry, furious and frustrated: the combination of feelings, very true to life, has been powerfully projected by the music. They look to Aron for some explanation of what has become of Moses, and Aron dreams. Perhaps this, perhaps that.

The orchestra plays delicate changes on the lustrous chords of God, making beautiful sounds, and the whole tragedy of the piece is revealed. Moses' idea, of the almighty, invisible God, could be stated in just two chords. The idea becomes theater only because of Aron's fascination with it   ?   a fascination that leads him to imagine, play, distort.

At this point the last of his distortions, the last of his "perhaps" speculations, is to suggest that perhaps Moses has been killed by his God. The people, surprised and appalled, repeat the idea: "Killed by his God?" And as his words come back to him, Aron (Philip Langridge) widens his eyes. It is not that he wishes his brother dead; what delights him, even more than his power over the crowd, is the notion of drama.

Here again, on an intimately human scale, is the entire tragedy. Aron's weakness for drama at the expense of truth, as represented by Moses, will lead to an orgy of bestiality in the "Dance Around the Golden Calf" and then to a permanent impasse as the opera ends, decisively and necessarily unfinished.

The moment is a key one, but the strength of this production rests on no single scene and no one performance. It is everywhere. As Moses, John Tomlinson has the same look he had before, of an ordinary man, deficient but unshakably determined. His voice, though, has grown. He sings less, using the freedom of Schoenberg's speech-song to find fiercely expressive regions of growl and lament. There is nothing bombastic. He is a heroic figure, but flawed and gnarled and touching.

Mr. Langridge fits perfectly with him as a mirror opposite. All the fluency and lyricism this Moses lacks, this Aron has. "Unrepresentable"   ?   one of Moses' string of adjectives about God, which sounds utterly resolute as Mr. Tomlinson delivers it in the German form, "Unvorstellbare"   ?   becomes in Mr. Langridge's supple voice a whole aria. He is persuasive, capricious, unrepentant, clever in everything except knowledge of himself: with his voice and his eyes and his nimble movements, he provides all the role requires, and he makes each word count.

The smaller parts are finely done. Matthew Polenzani projects an ardent tenor as the Youth. Sergei Koptchak makes a robust, no-nonsense Priest. Jennifer Welch, Heidi Skok, Andrea Trebnik and Malin Fritz tune their music beautifully together as the Four Naked Virgins.

Graham Vick's production is running more smoothly than before, and Ron Howell's choreography in the orgy fits the music, being at once brutal and clean, with moments of eeriness and shock. The members of the chorus are as physically present in the action as the dancers, and their singing is magnificent, at the thrilling close to the first act and everywhere else.

As for the orchestra, it is impossible to imagine the score sounding better, fuller, more expressive or more dramatic. James Levine, conducting, encourages his players to render it all: the hot, intense sound of one instrument at a time, like a desert horizon against Moses' voice in the opening scene, the luscious Viennese waltzes, the weird tones in the orgy of mandolin, tuned percussion and high woodwinds (a wild leap from E flat clarinet), the tightly contained passion in solos for violin and cello.

You just have to forget to expect major chords, and listen to what wonderful and meaningful sounds music can make without them. The final orchestral passage   ?   the yelling unison string melody that accompanies Moses' hard self-recognition   ?   makes the taut, sinuous, inevitable line of a whiplash.