Whether Penance should be assigned any parts?

Objections

Objection 1 : It would seem that parts should not be assigned to Penance. For it is the Divine power that works our salvation most secretly in the sacraments. Now the Divine power is one and simple. Therefore Penance, being a sacrament, should have no parts assigned to it.
Objection 2 : Further, Penance is both a virtue and a sacrament. Now no parts are assigned to it as a virtue, since virtue is a habit, which is a simple quality of the mind. In like manner, it seems that parts should not be assigned to Penance as a sacrament, because no parts are assigned to Baptism and the other sacraments. Therefore no parts at all should be assigned to Penance.
Objection 3 : Further, the matter of Penance is sin, as stated above (Question [84], Article [2]). But no parts are assigned to sin. Neither, therefore, should parts be assigned to Penance.