le should administer the
necessaries of life to those who minister the divine worship for the
welfare of the whole people even as it is the people's duty to
provide a livelihood for their rulers and soldiers and so forth.
Hence the Apostle proves this from human custom, saying (1 Cor. 9:7):
"Who serveth as a soldier at any time at his own charge? Who planteth
a vineyard and eateth not of the fruit thereof?" But the fixing of
the proportion to be offered to the ministers of divine worship does
not belong to the natural law, but was determined by divine
institution, in accordance with the condition of that people to whom
the law was being given. For they were divided into twelve tribes,
and the twelfth tribe, namely that of Levi, was engaged exclusively
in the divine ministry and had no possessions whence to derive a
livelihood: and so it was becomingly ordained that the remaining
eleven tribes should give one-tenth part of their revenues to the
Levites [*Num. 18:21] that the latter might live respectably; and
also because some, through negligence, would disregard this precept.
Hence, so far as the tenth part was fixed, the precept was judicial,
since all institutions established among this people for the special
purpose of preserving equality among men, in accordance with this
people's condition, are called "judicial precepts." Nevertheless by
way of consequence these institutions foreshadowed something in the
future, even as everything else connected with them, according to 1
Cor. 12, "All these things happened to them in figure." In this
respect they had something in common with the _ceremonial precepts,_
which were instituted chiefly that they might be signs of the future.
Hence the precept about paying tithes foreshadowed something in the
future. For ten is, in a way, the perfect number (being the first
numerical limit, since the figures do not go beyond ten but begin
over again from one), and therefore he that gave a tenth, which is
the sign of perfection, reserving the nine other parts for himself,
acknowledged by a sign that imperfection was his part, and that the
perfection which was to come through Christ was to be hoped for from
God. Yet this proves it to be, not a ceremonial but a judicial
precept, as stated above.

There is this difference between the ceremonial and judicial precepts
of the Law, as we stated above (I-II, Q. 104, A. 3), that it is
unlawful to observe the ceremonial precepts at the time of the