When the Catholic Church appears
to teach "new doctrines"
about Mary, it is often a
statement of truth against some
current errors or a
clarification of truths that have always
been taught and believed by
Christians through the centuries.
The Church believes that handing
on these truths participates
in the admonition of Paul.
2 Thessalonians 2:15
Therefore, brothers, stand firm and hold fast to the
traditions that you were taught, either by an oral
word) or by a letter (written tradition)