The theme often refers to a musical idea that is superordinate to the motif, possibly even composed of individual motifs, which guides and shapes a piece of music or a section of it. For that the theme is repeated and varied:

Thinking a theme means clarifying and demonstrating its construction through variation.1)

1) Markus Fahlbusch: Musikalischer Gedanke und Atonalität: Strukturmodelle musikalischen Denkens im II. Streichquartett op. 10 von Arnold Schönberg. H. Schneider 2006, S. 262