“Lent is ordered to preparing for the celebration of Easter, since the Lenten liturgy prepares for celebration of the Paschal Mystery both catechumens, by the various stages of Christian Initiation, and the faithful, who recall their own Baptism and do penance.”
(Universal Norms on the Liturgical Year, #27)
By the threefold discipline of fasting, almsgiving and prayer the church keeps Lent from Ash Wednesday until the evening of Holy Thursday. All of the faithful and the catechumens should undertake the serious practice of these three traditions. Failure to observe penitential days totally or a substantial number of such days must be considered serious.
“(On) weekdays of Lent, we strongly recommend participation in daily Mass and self-imposed observances of fasting. In light of grave human needs which weigh on the Christian conscience in all seasons, we urge particularly during Lent, generosity to local, national and world programs of sharing of all things needed to translate our duty to penance into a means of implementing the right of the poor to their part of our abundance.”
(U.S. Bishops statement on penitential observances, 1966.)