The three-part structure of the work approximates to that of Handel's three-act operas, with the "parts" subdivided by Jennens into "scenes". Each scene is a collection of individual numbers or "movements" which take the form of recitatives, arias and choruses.[15] There are two instrumental numbers, the opening Sinfony[n 2] in the style of a French overture, and the pastoral Pifa, often called the "pastoral symphony", at the mid-point of Part I.[18]In Part I, the Messiah's coming and the virgin birth are predicted by the Old Testament prophets. The annunciation to the shepherds of the birth of the Christ is represented in the words of Luke's gospel. Part II covers Christ's passion and his death, his resurrection and ascension, the first spreading of the gospel through the world, and a definitive statement of God's glory summarised in the "Hallelujah". Part III begins with the promise of redemption, followed by a prediction of the day of judgment and the "general resurrection", ending with the final victory over sin and death and the acclamation of Christ.[19] According to the musicologist Donald Burrows, much of the text is so allusive as to be largely incomprehensible to those ignorant of the biblical accounts.[15] For the benefit of his audiences Jennens printed and issued a pamphlet explaining the reasons for his choices of scriptural selections.[20]