Chapter — Wouters, Manual of Moral Theology
Chapter I. On the Object
I. Notion. Object is here understood as that toward which, insofar as it is subject to the rules of morals, a human act is borne per se. Thus another's property is the object of theft; God is the object of the act of love (St. Alphonsus, V, XXXVI; cf. St. Thomas, I-II, q. 18, a. 2, ad 1 and ad 2).
II. Morality from the object. A human act takes specific morality, goodness or malice, from its known object, good or evil. The reason is that an act takes specific morality from that toward which it is borne per se; such is the object (St. Thomas, I-II, q. 18, a. 2; St. Alphonsus, V, XXXVII). I have said "from its known object, good or evil," namely so that morality can be contracted or become formal; for nothing is willed unless known.
Nevertheless, circumstance and end, as we shall note later, sometimes destroy the goodness of the object. Moreover, if the object and the circumstances are indifferent, for example the act of walking, specific morality is taken from the end1 (St. Alphonsus, V, XXXVIII; XLI).
1 In this case circumstance or end is said to put on the account of the object. But when the matter is taken in this way, it can be said that even in this hypothesis specific morality is derived from the object.