Whether a vow consists in a mere purpose of the will?

❌ Objection 1 : It would seem that a vow consists in nothing but a purpose of the will. According to some [*William of Auxerre, Sum. Aur. III, xxviii, qu. 1; Albertus Magnus, Sent. iv, D, 38], "a vow is a conception of a good purpose after a firm deliberation of the mind, whereby a man binds himself before God to do or not to do a certain thing." But the conception of a good purpose and so forth, may consist in a mere movement of the will. Therefore a vow consists in a mere purpose of the will.

❌ Objection 2 : Further, the very word vow seems to be derived from "voluntas" [will], for one is said to do a thing "proprio voto" [by one's own vow] when one does it voluntarily. Now to "purpose" is an act of the will, while to "promise" is an act of the reason. Therefore a vow consists in a mere act of the will.

❌ Objection 3 : Further, our Lord said (Lk. 9:62): "No man putting his hand to the plough, and looking back, is fit for the kingdom of God." Now from the very fact that a man has a purpose of doing good, he puts his hand to the plough. Consequently, if he look back by desisting from his good purpose, he is not fit for the kingdom of God. Therefore by a mere good purpose a man is bound before God, even without making a promise; and consequently it would seem that a vow consists in a mere purpose of the will.