If you want to know what Jews believe in, look at their calendar.
Not fair, you say? Other faiths have lists, “I believe… I believe…” Why not Judaism?
Maimonides and others actually tried to compile lists of creeds. Maimonides, for example, formulated thirteen Ikkarim – principles of faith – which were later turned into a poem, Yigdal, which entered the synagogue liturgy.
But Maimonides was criticised, and some authorities such as the Arizal (Rabbi Isaac Luria) refused to include Yigdal in their prayer books, on the basis that the whole of Judaism is holy and there is no justification for singing out thirteen principles and giving them extra status.
Perhaps Hirsch’s dictum is a further response to Maimonides, even though Hirsch himself and the German Jewish liturgy which he followed did not exclude Yigdal.
When Hirsch spoke of our creed being our calendar he was saying that creeds only matter when they find expression in action.
The actions involved in our festivals show that we believe in God as Creator, Judge, Protector and Teacher, and in His dictates of truth, justice, freedom and peace.