The opera begins with a short, "strenuous" instrumental prelude, which forms the basis of the musical accompaniment to the opening congregational hymn; its first phrase is founded on a descending bass E-B-F, itself to become an important motif. Humphrey Carpenter notes that throughout the hymn the bass line is out of step with the singing, an effect which, he says, "suggests an adult world where purity is unattainable". Following the hymn, the Voice of God is accompanied, as it is in all his pre-flood warnings and declamations, by the E-B-F notes from the opera's opening bass line, sounded on the timpani. After Noye's response in recitative, the next musical episode is the entry of Noye's children and their wives, a passage which, Carpenter suggests, replaces the pessimism of the adult word with "the blissful optimism of childhood". The syncopated tune of the children's song is derived from the final line of Noye's recitative: "As God has bidden us doe".