Essentially, Lent is a biblical concept. Lent is a period of 40 days of penance in preparation for the solemn celebration of the Lord's Resurrection on Easter Sunday. Jesus, before beginning His earthly public ministry, fasted and prayed for 40 days and 40 nights (Mt. 4:1-11). As the Gospel continually reaffirms, penance is an important part of repentance (Mk. 1:15 cf. Mt. 6:16-18). And, Jesus provided us with the example of fasting for 40 days and nights.
The concept of 40 days existing as preparation was seen by Elijah, who fasted and journeyed to Horeb for 40 days (1 Kings 19:8). There are dozens of other references to the number 40 in the Old Testament.
The great liturgical Dom Gueranger writes that Lent was founded by the Apostles themselves:
The forty days' fast, which we call Lent, is the Church's preparation for Easter, and was instituted at the very commencement of Christianity. Our blessed Lord Himself sanctioned it by fasting forty days and forty nights in the desert; and though He would not impose it on the world by an express commandment (which, in that case, could not have been open to the power of dispensation), yet He showed plainly enough, by His own example, that fasting, which God had so frequently ordered in the old Law, was to be also practiced by the children of the new. The disciples of St. John the Baptist came, one day, to Jesus, and said to Him: 'Why do we and the pharisees fast often, but Thy disciples do not fast?' And Jesus said to them: 'Can the children of the Bridegroom mourn, as long as the Bridegroom is with them? But the days will come, when the Bridegroom shall be taken away from them, and then they shall fast.'The Baltimore Catechism:
Hence we find it mentioned, in the Acts of the Apostles, how the disciples of our Lord, after the foundation of the Church, applied themselves to fasting. In their Epistles, also, they recommended it to the faithful. Nor could it be otherwise. Though the divine mysteries whereby our Saviour wrought our redemption have been consummated, yet are we still sinners: and where there is sin, there must be expiation.
The apostles, therefore, legislated for our weakness, by instituting, at the very commencement of the Christian Church, that the solemnity of Easter should be preceded by a universal fast; and it was only natural that they should have made this period of penance to consist of forty days, seeing that our divine Master had consecrated that number by His own fast.
Q. 1342. When do fast days chiefly occur in the year?
A. Fast days chiefly occur in the year during Lent and Advent, on the Ember days and on the vigils or eves of some great feasts. A vigil falling on a Sunday is not observed.
Q. 1343. What do you mean by Lent, Advent, Ember days and the vigils of great feasts?
A. Lent is the seven weeks of penance preceding Easter. Advent is the four weeks of preparation preceding Christmas. Ember days are three days set apart in each of the four seasons of the year as special days of prayer and thanksgiving. Vigils are the days immediately preceding great feasts and spent in spiritual preparation for them.
Q. 1344. What do you mean by days of abstinence?
A. By days of abstinence I mean days on which no meat at all may be taken (complete abstinence) or on which meat may be taken only once a day (partial abstinence). This is explained in the regulations for Lent. All the Fridays of the year are days of abstinence except when a Holyday of obligation falls on a Friday outside of Lent.
Q. 1345. Are children and persons unable to fast bound to abstain on days of abstinence?
A. Children, from the age of seven years, and persons who are unable to fast are bound to abstain on days of abstinence, unless they are excused for sufficient reason.
Q. 1346. Why does the Church command us to fast and abstain?
A. The Church commands us to fast and abstain, in order that we may mortify our passions and satisfy for our sins.
