From The Rule of St. Benedict (Regula) , Chapter 49, on the Observance of Lent.
A Monk’s life should at all times resemble a continual Lent, but few have such virtue.
Thus, we encourage everyone during Lent to live in all purity, and during this holy season to wash away all the negligences of other times.
This we worthily accomplish if we refrain from all defects, and apply ourselves to tearful prayer, to reading, to compunction of heart, and abstinence.
In these days, therefore, we should add something over and above our usual task, such as private prayers, and abstinence from meat and drink.
Everyone should offer to God, with his own free will and with the joy of the Holy Spirit, something above the measure assigned to him.
That is to say, let him withhold from his body something in the way of food, drink, sleep, talk, laughter, and do so with spiritual joy and desire, awaiting the holy feast of Easter.
Nevertheless, let each one tell the Abbot what he intends to offer, and do it at his desire and with his consent, for whatever is done without the permission of the spiritual Father, should be considered presumption and vain glory, and merit no reward.
All things, therefore, must be done with the approval of the Abbot.