It begins with the persistent repetition of arpeggiated chords, reminiscent of the struggle of being suppressed and confined to one place. Although it is in sonata form, there is no repetition of the exposition, and the proportion of the recapitulation and subsequent sections to the entire movement is very large. This is because, from the recapitulation of the secondary theme onwards, part of the development section is also recapitulated, making the entire coda extensive (if the section from the recapitulation of the development onwards to the end of the movement is considered the coda, its measure count exceeds one-quarter of the entire movement). If the somewhat formalized framework of sonata form that we currently conceive differs from Mendelssohn's formal ideas, then the section to be repeated in the recapitulation might not necessarily extend only to the end of the secondary theme group. While the diversity of sonata form has been repeatedly discussed, the structure of this first movement prompts us to reconsider the conventional divisions of exposition, development, and recapitulation.

The realm of the tonic key, C minor, consists of multiple themes (in such cases, referred to as a "primary theme group" rather than a "primary theme"); after the non-melodic and rough arpeggiated chord theme, the violin finally presents a melodic theme. After another return of the opening theme, the music reaches the relative major, E-flat major, where the strings play a flowing and bright secondary theme characteristic of Mendelssohn.

After a short transition, the development section begins with imitation between the piano and violin based on the movement's opening theme. The writing style of the development section is also incorporated into the recapitulation. For instance, in the recapitulation of the movement's opening theme, contrary to the exposition, while the strings first present the arpeggiated chord motif, the piano plays triplet arpeggiated chords very similar to those that appeared with the secondary theme melody in the development section. And when the arpeggiated chords of the primary theme shift from the strings to the piano, the violin, in turn, imitates the piano, creating a texture corresponding to the beginning of the development section. It can be said that the recapitulation integrates the content of both the exposition and the development. Previously presented material is still utilized in fresh ways in the coda. Here, it is also noteworthy that the strings superimpose the same theme in augmented note values over the piano's opening arpeggiated chord theme of the movement.