Bach’s musical style arose from his extraordinary fluency in contrapuntal invention and motivic control, his flair for improvisation at the keyboard, his exposure to South German, North German, Italian and French music, and his apparent devotion to the Lutheran liturgy. His access to musicians, scores and instruments as a child and a young man, combined with his emerging talent for writing tightly woven music of powerful sonority, appear to have set him on course to develop an eclectic, energetic musical style in which foreign influences were injected into an intensified version of the pre-existing German musical language. Throughout his teens and 20s, his output showed increasing skill in the large-scale organisation of musical ideas, and the enhancement of the Buxtehudian model of improvisatory preludes and counterpoint of limited complexity. The period 1713–14, when a large repertoire of Italian music became available to the Weimar court orchestra, was a turning point. From this time onwards, he appears to have absorbed into his style the Italians’ dramatic openings, clear melodic contours, the sharp outlines of their bass lines, greater motoric and rhythmic conciseness, more unified motivic treatment, and more clearly articulated schemes for modulation.

Bach’s apparently devout, personal relationship with the Christian God in the Lutheran tradition and the high demand for religious music of his times inevitably placed sacred music at the centre of his repertory; more specifically, the Lutheran chorale hymn tune, the principal musical aspect of the Lutheran service, was the basis of much of his output. He invested the chorale prelude, already a standard set of Lutheran forms, with a more cogent, tightly integrated architecture, in which the intervallic patterns and melodic contours of the tune were typically treated in a dense, contrapuntal lattice against relatively slow-moving, overarching statements of the tune.

Bach's deep knowledge of and interest in the liturgy led to his developing intricate relationships between music and linguistic text. This was evident from the smallest to the largest levels of his compositional technique. On the smallest level, many of his sacred works contain short motifs that, by recurrent association, can be regarded as pictorial symbolism and articulations of liturgical concepts. On the largest level, the large-scale structure of some of his sacred vocal works is evidence of subtle, elaborate planning.

Beyond these specific musical features arising from Bach’s religious affiliation is the fact that he was able to produce music for an audience that was committed to serious, regular worship, for which a concentrated density and complexity was accepted. His natural inclination may have been to reinvigorate existing forms, rather than to discard them and pursue more dramatic musical innovations. Thus, Bach’s inventive genius was almost entirely directed towards working within the structures he inherited, according to most critics and historians.

Bach’s inner personal drive to display his musical achievements was evident in a number of ways. The most obvious was his successful striving to become the leading virtuoso and improviser of the day on the organ. Keyboard music occupied a central position in his output throughout his life, and he pioneered the elevation of the keyboard from continuo to solo instrument in his numerous harpsichord concertos and chamber movements with keyboard obbligato, in which he himself probably played the solo part.