How can I differentiate between a mass and oratorio?

In order to
distinguish between a mass and an
oratorio it is important to examine their formats and subject
matter. Both
musical pieces deal with religious subjects, and can be performed in churches
and
cathedrals.

The musical mass follows a set format,
which is in sequence of
the celebration of the liturgy of the Catholic,
Lutheran, or Protestant faiths. Early masses
were written for the Ordinary of
Liturgy so that daily masses could have musical components. A
mass can be
sung a cappella, without musical accompaniment, or it
can
accompanied by instruments from a singular organ to a full orchestra.
Throughout history the
musical mass has changed to include choirs, modern
instruments, and participation by those
attending the service, instead of
being sung solely by a choir. Although these changes occurred,
the format and
purpose, of presenting the liturgy through music, remains the same.

The subject matter of oratorios is also religiousoratorios portray the lives of
the
saints or passages from the Bible. The purpose of an oratorio differs in
that it is entertaining
and theatrical. Although the characters do not often
interact, the oratorio includes an
orchestra, choir, and soloists. This form
of religious entertainment is devoid of scenery and
props, and is considered
to be a concert piece.

Therefore, both masses and

oratorios are religious pieces of music, but a mass follows the format of the liturgy
of
worship, while an oratorio is performed as religious
entertainment.