For the Missa solemnis, as for virtually all music conceived for voices, the text must be the starting-point for a discussion of form. Indeed, it offers the simplest explanation for many of the basic features of Beethoven's Mass: the ternary shape of the Kyrie; the relatively diffuse design of the Gloria and Credo in comparison with the other movements; the fact that the Sanctus and Agnus Dei both end in different keys from those in which they began.

A detailed look at the text usually uncovers elements of what is often called ‘word-painting’, the musical characterization of a word or what it stands for. Some of these are self-evident, for example, rising and falling vocal lines for ‘ascendit’ and ‘descendit’, or the contrast between animated music in a high register and quiet sounds in a low register to express the opposition of ‘Gloria in excelsis Deo’ and ‘et in terra pax’.

Beethoven often relied on established conventions whereby the music is sensibly related to the words without being dictated by them. The fact that the Gloria and Credo texts end with the same word, ‘amen’, may suggest that the endings were conceived along similar lines, but cannot actually determine the nature of the similarity; it is the observance of a longstanding tradition that makes both of these endings extended essays in polyphonic composition, that is, fugues.