Thus, for instance, Prescott tells us:

Terror, not love, was the spring of education with the
Aztecs....Such was the crafty policy of the priests, who, by
reserving to themselves the business of instruction, were
enabled to mould the young and plastic mind according to
their own wills, and to train it early to implicit reverence
for religion and its ministers.

The historian goes on to indicate the economic harvest of this
teaching:

To each of the principal temples, lands were annexed for the
maintenance of the priests. The estates were augmented by
the policy or devotion of successive princes, until, under
the last Montezuma, they had swollen to an enormous extent,
and covered every district of the empire.

And this concerning the frightful system of human sacrifices, whereby
the priestly caste maintained the prestige of its divinities:

At the dedication of the temple of Huitzilopochtli, in 1486,
the prisoners, who for some years had been reserved for the
purpose, were ranged in files, forming a procession nearly
two miles long. The ceremony consumed several days, and
seventy thousand captives are said to have perished at the
shrine of this terrible deity.

The same system appears in Professor Jastrow's account of the
priesthood of Babylonia and Assyria: