Die Schuldigkeit des ersten Gebots (complete title in historical spelling: Die Schuldigkeit Des ersten und fürnehmsten Gebotes; The Obligation of the First and Foremost Commandment), K. 35, is a sacred musical play (geistliches Singspiel) composed by Wolfgang Amadeus Mozart in 1767 when he was 11 years old.

[2] Part 1 of the opera was first performed on March 12, 1767, in the Knight's Hall of the Palace of the Archbishop, the Salzburg Residenz.

[1] Mozart composed the work at age 11 with the help of his two teachers, Michael Haydn and Anton Cajetan Adlgasser.

The characters of the opera are two tenors: Christgeist and Christ (a Christian), and three sopranos: Barmherzigkeit, Gerechtigkeit, and Weltgeist.

Part I of the opera was first performed on 12 March 1767 in the Knight's Hall of the Palace of the Archbishop, Salzburg.