Thomas Aquinas

“ Now just as a thing acquires an aspect of good through being deputed to a good end, so does a thing assume a divine character through being deputed to the divine worship, and thus a certain reverence is due to it, which reverence is referred to God. Therefore whatever pertains to irreverence for sacred things is an injury to God, and comes under the head of sacrilege. ”

“ Now holiness is ascribed, not only to sacred persons, namely, those who are consecrated to the divine worship, but also to sacred places and to certain other sacred things. And the holiness of a place is directed to the holiness of man, who worships God in a holy place. ”

“ When one punishment is not sufficient to deter a man from sin, a double punishment must be inflicted. Wherefore it was necessary to inflict some kind of temporal punishment in addition to the punishment of excommunication, in order to coerce those who despise spiritual things. ”

“ Nothing prevents one specific kind of sin being found in various generic kinds of sin, inasmuch as various sins are directed to the end of one sin, just as happens in the case of virtues commanded by one virtue. In this way, by whatever kind of sin a man acts counter to reverence due to sacred things, he commits a sacrilege formally ”

“ If money were exacted without a reasonable cause, this would seem to involve an occasion of covetousness. But when it is exacted for the purpose of man's correction, it has a manifest utility, and consequently involves no occasion of avarice. ”

“ On the contrary, Isidore says (Etym. x) that "a man is said to be sacrilegious because he selects," i.e. steals, "sacred things."
I answer that, As stated above (Q [81] , A [5] ; FS, Q [101] , A [4] ) , a thing is called "sacred" through being deputed to the divine worship. ”