not the expiation of the cross;
that the mission of Christ was something more than to set a good
example; that faith was not estimation merely; that regeneration was not
a mere external change of life; that the Divine government was a
perpetual interference to bring good out of evil, even if it were in
accordance with natural law. He knew that the boastful philosophy by
which some sought to bolster up Christianity was that against which the
apostles had warned the faithful. He knew that the Church was attacked
in her most vital points, even in doctrines,--for "as a man thinketh,
so is he."

So he fearlessly entered the lists against the heretics, most of whom
were enrolled among the Manicheans, Pelagians, and Arians.

The Manicheans were not the most dangerous, but they were the most
offensive. Their doctrines were too absurd to gain a lasting foothold in
the West. But they made great pretensions to advanced thought, and
engrafted on Christianity the speculations of the East as to the origin
of evil and the nature of God. They were not only dreamy theosophists,
but materialists under the disguise of spiritualism. I shall have more
to say of these people in the next Lecture, on Augustine, since one of
his great fights was against the Manichean heresy. So I pass them by
with only a brief allusion to their opinions.

The Arians were the most powerful and numerous body of heretics,--if I
may use the language of historians,--and it was against these that
Ambrose chiefly contended. The great battle against them had been fought
by Athanasius two generations before; but they had not been put down.
Their doctrines extensively prevailed among many of the barbaric
chieftains, and the empress herself was an Arian, as well as many
distinguished bishops. Ambrose did not deny the great intellectual
ability of Arius, nor the purity of his morals; but he saw in his
doctrines the virtual denial of Christ's divinity and atonement, and a
glorification of the reason, and an exaltation of the will, which
rendered special divine grace unnecessary. The Arian controversy, which
lasted one hundred years, and has been repeatedly revived, was not a
mere dialectical display, not a war of words, but the most important
controversy in which theologians ever enlisted, and the most vital in
its logical deductions. Macaulay sneers at the _homoousian_ and the
_homoiousian_; and when viewed in a technical point of view, it may seem
to many frivolous an