read grammar to the people in place of the Gospel lesson.

Hence also Ambrose writes concerning Luke:

=Profane writings should be read that they may not be unknown.=

Some we read (_o_) that we may not neglect (_a_) them; we read
that we may not be ignorant of them; we read not that we may
embrace them but that we may reject them.(_b_)

So Jerome on the Epistle to Titus:

=Grammar should be read in order that through it the Sacred
Scriptures may be understood.=

If anyone[V] has learned grammar or dialectics in order to have
the ability to speak correctly and to discriminate between the
true and the false, we do not blame them. Geometry (_c_) and
Arithmetic and Music contain truth in their own range of
knowledge, but that knowledge is not the knowledge of piety. The
knowledge of piety is,--to know the law, to understand the
prophets, to believe the Gospel, (and) not to be ignorant of the
Apostles. Moreover the teaching of the grammarians can contribute
to life, provided it has been applied to its higher uses.

Idem:

=From the example of Daniel it is established that it is not a
sin to be learned in profane literature.=[W]