Wikipedia
Jephtha ( HWV 70) is an oratorio (1751) by Handel with a libretto by the Rev. Thomas Morell, based on the story of Jephtha in Judges (Chapter 11) and Jephthas sive votum - "Jeptha or the Vow" (1554) by George Buchanan. Whilst writing Jephtha, Handel was increasingly troubled by his gradual loss of sight, and this proved to be his last oratorio. In the autograph score, at the end of the chorus "How dark, O Lord, are thy decrees" he wrote "Reached here on 13 February 1751, unable to go on owing to weakening of the sight of my left eye."
The story revolves around Jephtha's rash promise to the Almighty that if he is victorious, he will sacrifice the first creature he meets on his return. He is met by his beloved daughter Iphis. Unlike the original Biblical story, an angel intervenes to stop the sacrifice, and Iphis only needs to dedicate her life to the Lord. In contrast, the Biblical story strongly implies that her father chose to sacrifice her, but a short reprieve is arranged, after which Iphis dutifully returns and was killed, but some Christians have suggested that she was instead dedicated to the Lord and required to observe a life of perpetual virginity. Regardless, however, the Bible makes no mention of an angel stopping what occurred. Staged performance of material based on biblical subjects was forbidden in Great Britain at the time the work was premiered. Handel's final masterpiece was presented at the Covent Garden on 26 February 1752, with the composer conducting, and with a cast that included John Beard (tenor) as Jephtha and two divas of the opera stage, Giulia Frasi, Handel's prima donna since 1749, and Caterina Galli. It was presented without scenery or costumes, divided into three acts.
Jephtha is principally remembered for the dramatic recitative Deeper, and deeper still, and the aria Waft her, angels, thro' the skies, one of Handel's most beautiful airs. The two passages occur separately within the oratorio, but during the 19th century these were often performed together in concert, as if the recitative directly preceded the aria.