French overture
The first Sunday of Advent begins the liturgical year. Bach marked it by creating the opening chorus, "" (Now come, Saviour of the Gentiles), as a chorale fantasia in the style of a French overture, which follows the sequence slow – fast (fugue) – slow. In a French opera performance, the King of France would have entered during the overture; Bach greets a different king. Two of the four lines of the chorale melody are combined in the first slow section, line three is treated in the fast section, and line four in the final slow section. The melody of line 1 is first presented in the continuo, then sung by all four voices one after another, accompanied by a solemn dotted rhythm in the orchestra. Line 2 is sung by all voices together, accompanied by the orchestra. Line 3 is a fast , with the instruments playing , marked "gai". Line 4 is set as line 2. Wolff notes that Bach possibly followed the model of an opera by Agostino Steffani, "Henrico Leone", which uses a chorus in a French overture.