Tiruvalluvar

“ The hotter glows the fining fire, the gold the brighter shines;
The pain of penitence, like fire, the soul of man refines.
Just as gold is purified as heated in the fire, will those shine, who have endured the burning of pain (in frequent austerities) . ”

“ He causes others, is the type of 'penitence'.
The nature of religious discipline consists, in the endurance (by the ascetic) of the sufferings which it brings on himself, and in abstaining from giving pain to others. ”

“ That what they wish may, as they wish, be won,
By men on earth are works of painful 'penance' done.
Religious dislipline is practised in this world, because it secures the attainment of whatever one may wish to enjoy (in the world to come) . ”