On weekdays of Lent (Monday through Friday) the celebration of the Divine
Liturgy is strictly forbidden. They are =non-liturgical days= (with one
possible exception, the Feast of Annunciation). The reason for this rule
is that the Eucharist is by its very nature a festal celebration, the
joyful commemoration of Christ's Resurrection and glorification and His
presence among His disciples. But twice a week, on Wednesday and Fridays,
the Church prescribes the celebration after Vespers, i.e., in the
evening, of the =Liturgy of the Presanctified Gifts=. It consists of
solemn Great Vespers and communion with the Holy Gifts consecrated on the
previous Sunday. These days being days of =strict fasting= (theoretically:
complete abstinence), are "crowned" with the partaking of the Bread of
life, the ultimate fulfillment of our efforts....
"... When Thou has freed us and Thy faithful people from all
impurities, sanctify the souls and bodies of all of us with
a sanctification not to be taken away; that with a clear
conscience, peaceful presence and enlightened hearts we may
participate in those divine Sacraments, and be quickened
through them and become one with Thy Christ Himself, our
true God, Who said: Who so eats My Flesh and drinks My Blood,
abides in Me and I in Him. So that by Thy Word dwelling in us
and walking with us we may become, O Lord, a temple of Thine
all-holy and adored spirit ..."
(=Prayer at the Presanctified Liturgy=)