Die Schuldigkeit des ersten Gebotes is an opera, K. 35, composed by Wolfgang Amadeus Mozart in 1767. It is Mozarts first opera or, more specifically, sacred drama, as is suggested by the translated name The Obligation of the First and Foremost Commandment. The libretto is by Ignaz Anton von Weiser. It was first performed on March 12, 1767 in the Knight's Hall of the Palace of the Archbishop, Salzburg.

Only the first part of the opera is composed by Mozart, the second and third were completed by Michael Haydn and Anton Cajetan Adlgasser respectively.

Dramatis Personæ

• Gerechtigkeit [translated as Divine Justice] (soprano)
• Christgeist [translated as Spirit of Christianity] (tenor)
• Barmherzigkeit [translated as Divine Mercy] (soprano)
• Ein lauer und hinnach eifriger Christ [translated as a half-hearted but later zealous Christian] (tenor)
• Weltgeist [translated as Worldliness] (soprano)