/summa/XP/XPII/XP_Q15:
We must now consider the means of making satisfaction, under which head there are three points of inquiry:
(1) Whether satisfaction must be made by means of penal works?
(2) Whether the scourges whereby God punishes man in this life, are satisfactory?
(3) Whether the works of satisfaction are suitably reckoned, by saying that there are three, viz. almsdeeds, fasting, and prayer?