In S. Luke's Gospel[71] we read: _Let us serve Him in holiness and justice._ But to serve God comes under religion. Hence religion is the same as sanctity.
The word "sanctity" seems to imply two things. First, it seems to imply _cleanness_; and this is in accordance with the Greek word for it, for in Greek it is _hagios_,[72] as though meaning "without earth." Secondly, it implies _stability_, and thus among the ancients those things were termed _sancta_ which were so hedged about with laws that they were safe from violation; similarly a thing is said to be _sancitum_ because established by law. And even according to the Latins the word _sanctus_ may mean "cleanness," as derived from _sanguine tinctus_, for of old those who were to be purified were sprinkled with the blood of a victim, as says S. Isidore in his _Etymologies_.[73]
And both meanings allow us to attribute sanctity to things which are used in the Divine worship; so that not men only, but also temples and vessels and other similar things are said to be sanctified by reason of their use in Divine worship. _Cleanness_ indeed is necessary if a man's mind is to be applied to God. For the mind of man is stained by being immersed in inferior things, as indeed all things are cheapened by admixture with things inferior to them--silver, for instance, when mixed with lead. And for our minds to be knit to the Supreme Being they must needs be withdrawn from inferior things. Without cleanness, then, the mind cannot be applied to God. Hence in the Epistle to the Hebrews[74] it is said: _Follow peace with all men, and holiness, without which no man shall see God._
_Stability_ is also required if the mind is to be applied to God. For the mind is applied to Him as to the Ultimate End and First Principle, and consequently must be immovable. Hence the Apostle says: _For I am sure that neither death nor life shall separate me from the love of God._[75]
Sanctity, then, is said to be that whereby man's mind and its acts are applied to God. Hence sanctity does not differ from religion essentially, but in idea only. For by religion we mean that a man offers God due service in those things which specially pertain to the Divine worship--sacrifices, for example, and oblations, etc.; but by sanctity we mean that a man not only offers these things, but also refers to God the works of the other virtues, and also that a man disposes himself by good works for the Divine worship.