Brief formal statements of belief exist in several traditions, and they tend to appear at particular moments rather than at the beginning. The circumstances shaped the wording.
Growth creates a need for portability
A small community can transmit its understanding by living together. A dispersed one, with congregations in many places, cannot rely on that.
A short statement travels with a traveller and can be memorised by people who cannot read, which makes it usable in places where manuscripts are scarce and instruction is intermittent.
The compression is functional. A summary short enough to recite is short enough to check against, which is the purpose such statements serve.
Disputes determine which phrases appear
Summary statements are rarely balanced overviews. They dwell at length on points that were contested and pass quickly over matters nobody disagreed about.
The proportions are therefore historical evidence. A clause elaborated at unusual length marks a controversy that was live when the wording was settled.
Because of this, reading a creed as a complete account of a tradition misreads the genre. It is a boundary marker rather than a syllabus.
Ritual use fixed the wording
Many such statements entered regular liturgical use, recited at set points or at admission to the community, which stabilised the text quickly.
Once a form is said aloud by an entire assembly, changing it becomes difficult, since the congregation itself holds the version it knows.
This is one reason later disagreements over wording became so charged. Altering a phrase meant altering something people had recited for their whole lives.
Not every tradition produces them
Some traditions define membership by practice, lineage or observance rather than by assent to a set of propositions, and consequently produce nothing that resembles a creed at all.
Others have compact declarative formulas that function differently, serving as affirmations made in worship rather than as tests of doctrinal boundary.
The variation reflects genuinely different understandings of what belonging consists in, and comparing the texts without that context is misleading.
What the form cannot do
A statement short enough to memorise cannot carry its own interpretation, and communities reciting identical words have understood them differently.
Traditions handle this with commentary, catechism and teaching, which sit alongside the formula and are where most of the actual explanation happens.
The brevity that makes the form useful is also what makes those supporting materials necessary, and the two have generally developed together.