This oratorio is a leisurely setting comprising eight arias and a duet, all da capo, of an episode in the Israelites’ long journey from Egypt to the land of Canaan as recounted in the book of Numbers. The people rail against God and Moses for bringing them ‘out of Egypt to die in the wilderness’; for which God – egged on in this retelling, it must be said, by Moses – punishes them by sending the ‘fiery serpents’ of the title to bite them. Duly penitent, the people beg Moses to pray for relief: God relents, instructing Moses to make a serpent of brass and put it on a pole; on seeing which, those who have been bitten will recover. It is not stated whether the bitten dead will be revived.

Hasse is noted for being the favourite composer of the librettist Metastasio, but the text here is by one Bonaventura Bonomo, who adds a Christian gloss to the Old Testament story: the people are punished for scorning the manna from heaven, which looks forward to the bread of the Last Supper; and the brass serpent, a symbol of life, foreshadows Christ on the cross. Hasse composed it around 1733 for the girls of the Ospedale degli Incurabili, one of the four famous orphanages in Venice. All female voices, therefore; but there is only one such on this recording, and that is Julia Lezhneva as the Angel.

Hasse gives one aria to the subsidiary characters and two apiece to Moses and the Angel. They are so astonishingly ornate in places that one can only marvel at the evident virtuosity of his orphans. And he bestows great care on the recitatives: at significant moments, such as the Angel speaking of the manna and bread, or Moses foretelling Christ’s redemption of the world, there’s an almost imperceptible transition from secco to accompagnato.

The action begins with Eliab complaining to Eleazar about the Israelites’ plight. David Hansen’s singing is a bit wild, but apt enough. This provokes the wrath of Moses, who calls down thunderbolts and hurricanes. Philippe Jaroussky makes the most of his first aria, where the violence is more in the words than the music. It’s left to Nathanael to describe both serpents and tempests, the former appropriately illustrated by sinuous phrases in the strings. Jakub Józef Orliński catches the mood perfectly, his coloratura offset by fierce octaves in the accompaniment.

The sole duet is given to Eleazar and Joshua: Carlo Vistoli and Bruno de Sá praise God in beautifully blended chains of thirds that would not be out of place in one of Hasse’s many operas. Julia Lezhneva invests the Angel’s reference to the manna from heaven with an other-worldly tenderness. And she demonstrates such wonderful breath control in the semiquaver runs of ‘Aura beata’ that I can almost forgive her for the cadenza: OTT isn’t the half of it. Les Accents under Thibault Noally, just strings and continuo, play with impeccable style. It is all very nicely done.