“Sound the trumpet at the new moon,” says the Psalmist, “in the notable day of your feast” (Psalm 80:4 [LXX]).
This injunction is prophetic….
The Lord says: “Be not, as the hypocrites, of a sad countenance, but anoint thine head, and wash thy face” (Matthew 6:16-17).
Let us, therefore, exhibit the demeanor that we have been taught, not being doleful about the coming days, but maintaining a joyful attitude, as befits holy people.
No one who desponds is crowned; no one who sulks sets up a trophy of victory.
Do not be sullen while you are being healed.
It would be absurd not to rejoice over the health of your soul, but rather to be distressed over a change of diet and to give the impression of setting more store by the pleasure of your stomach than by the care of your soul.
For satiety brings delight to the stomach, whereas fasting brings profit to the soul.
Be of good cheer, for the physician has given you a medicine that destroys sin.
For…fasting—a remedy truly worthy of its appellation—when introduced into the soul, kills off the sin that lurks deep within it.
“Anoint thine head, and wash thy face” Matthew 6:17). This sentence summons you to mysteries. One who has been anointed has received unction; he who has been washed has been cleansed.
Apply this injunction to your inner members. Wash your soul clean of sins. Have your head anointed with holy oil, so that you might become a partaker of Christ, and approach the fast in this spirit.
Do not disfigure your face as do the hypocrites (St. Matthew 6:16). The face is disfigured when one’s inner disposition is obscured by a sham external appearance, concealed by falsehood as if beneath a veil.
An actor in a theatre is one who assumes someone else’s persona…. Likewise, in this life, as if on some stage, the majority of people turn their existence into a theatre, entertaining one thing in their hearts, but displaying something else to men by their outward appearance.
Therefore, do not disfigure your face. Whatever you may be, appear as such. Do not transform yourself into a sullen person, seeking the glory that comes from appearing to be abstemious.
For there is no profit in trumpeting your good deeds, nor any gain in advertising your fasting. Things that are done for outward show do not yield any fruit in the age to come, but terminate in human praise.
Run with gladness to the gift of the fast. Fasting is an ancient gift, which does not grow old or become outmoded, but is ever renewed and flourishes with vigor.
Basil the Great (330-379): On Fasting 1-2, translated from the Greek original in Patrologia Græca, Vol. XXXI, cols. 164A-184C @ Old Calendar Orthodox Church of Greece.