Because he is illegitimate, Jephtha is driven out of Gilead by his half-brothers according to the Old Testament Book of Judges. The people of Israel, however, choose him as the commander of their army. Before he goes to battle against the Ammonites, who are occupying the Israelites’ land, he swears an oath. Whatever emerges first from his house he will burn as a sacrifice to the Lord. Iphis, Jephtha’s daughter, is the first to leave the house. But at the behest of an angel she is not sacrificed. Instead she serves God from that day on as a virgin priestess.
In this way, librettist Reverend Thomas Morell replaced the vengeful God of the Old Testament with a merciful God in accordance with Anglican theology. Following a four-month trip on the continent, Handel had asked the multitalented Morell to write him a libretto for an oratorio. Due to the problems Handel had with his eyes the work took eight months to complete and he borrowed passages from other composers that he had got to know on his travels. The premiere in 1752 was the last premiere of a newly composed work that Handel conducted himself. That same year he lost his eyesight entirely. Jephtha was his last oratorio.