It has been a long time since I posted anything on Thomas, though I do keep reading a questio a day. A real pearl today, I think (I-IIQ84:1):
According to some, covetousness may be understood in different ways. First, as denoting inordinate desire for riches: and thus it is a special sin. Secondly, as denoting inordinate desire for any temporal good: and thus it is a genus comprising all sins, because every sin includes an inordinate turning to a mutable good, as stated above (Question 72, Article 2). Thirdly, as denoting an inclination of a corrupt nature to desire corruptible goods inordinately: and they say that in this sense covetousness is the root of all sins, comparing it to the root of a tree, which draws its sustenance from earth, just as every sin grows out of the love of temporal things.
Now, though all this is true, it does not seem to explain the mind of the Apostle when he states that covetousness is the root of all sins. For in that passage he clearly speaks against those who, because they ”will become rich, fall into temptation, and into the snare of the devil . . . for covetousness is the root of all evils.” Hence it is evident that he is speaking of covetousness as denoting the inordinate desire for riches. Accordingly, we must say that covetousness, as denoting a special sin, is called the root of all sins, in likeness to the root of a tree, in furnishing sustenance to the whole tree. For we see that by riches man acquires the means of committing any sin whatever, and of sating his desire for any sin whatever, since money helps man to obtain all manner of temporal goods, according to Ecclesiastes 10:19: ”All things obey money”: so that in this desire for riches is the root of all sins.