Today’s second reading in Office of Readings is from Saint Cyril on the need for the creed as a synopsis of the Gospel and the biblical faith. The red annotations are my own comments.

Saint Cyril of Jerusalem On the Faith and the Creed
(Patroligia Graeca, 33, 519-523)

In learning and professing the faith, you must accept and retain only
the Church’s present tradition, confirmed as it is by the Scriptures [we must accept the Church’s “tradition” as confirmed by the Scriptures – that’s not Luther’s sola scriptura folks].
Although not everyone is able to read the Scriptures, some because
they have never learned to read, others because their daily activities
keep them from such study, still so that their souls will not be lost
through ignorance, we have gathered together the whole of the faith
in a few concise articles. [the formulation of a “creed” then is for salvation – it summarizes the Gospel content]

Now I order you to retain this creed for your nourishment
throughout life and never to accept any alternative, not even if I
myself were to change and say something contrary to what I am now
teaching, not even if some angel of contradiction, changed into an
angel of light, tried to lead you astray. For even if we, or an angel from heaven, should preach to you a gospel contrary to that which you have now
received, let him be accursed in your sight. [Again the “creed” is the objective Gospel of Christ and St Cyril invokes St Paul’s anathema regarding it.]

So for the present be content to listen to the simple words of the
creed and to memorize them; at some suitable time you can find
the proof of each article in the Scriptures [first we assent to the Church’s teaching – and then we find that it is based on Scripture – not the order of things here – again not Luther’s sola scriputra]. This summary of the
faith was not composed at man’s whim, the most important sections
were chosen from the whole Scripture to constitute and complete
a comprehensive statement of the faith. Just as the mustard seed
contains in a small grain many branches, so this brief statement of
the faith keeps in its heart, as it were, all the religious truth to be
found in Old and New Testament alike [the Creed itself is built on Scripture as a synopsis]. That is why, my brothers,
you must consider and preserve the traditions you are now receiving [so the creed is a set of traditions derived from Apostolic teaching, summarizing Scripture, and must be preserved by catechumens from baptism till death].
Inscribe them across your heart.

As a completely random thought based on Saint Cyril, it is truly wonderful that the Catholic Church as preserved the catechumenate. Nobody talks about this, but the Catholic catechumanate (liturgical training of inquirers for baptism), is further proof of the Catholic Church’s ecclesiastical understanding of justification.