Today, a day before the suffering of our Lord and Saviour Jesus Christ for our sins remission we do commemorate the day of the Last Supper or (The Supper of Mysteries) in the Orthdox Church.
According to our Church tradition today is the day on which the saviour has established the Church mystery of the Sacrements! (Eucharist)
Here are the exact passages from (Matthew 26:26-28), where by the word of the Lord the Eucharist was established:
“Now as they were eating, Jesus took bread, and blessed, and broke it, and gave it to the disciples and said, ‘Take, eat; this is my body.’ And he took a cup, and when he had given thanks he gave it to them, saying, ‘Drink of it, all of you; for this is my blood of the covenant, which is poured out for many for the forgiveness of sins.’” (Mt. 26:26-28)
The feast is celebrated with a morning Holy Liturgy among all Eastern Orthodox Churches around the world.
It’s common that many layman do confess and take the sacraments on this date.
Before sacraments are received we the layman confess our unworthiness for Christ and beg for him to make us worthy to receive the communion with the prayer:
I believe, O Lord, and I confess that Thou art truly the Christ, the Son of the Living God, who camest into the world to save sinners, of whom I am the first (see 1 Tim 1:15).
I believe also that this is truly Thine own most pure Body, and that this is truly Thine own most precious Blood. Therefore I pray Thee: Have mercy upon me and forgive me my transgressions, committed in word and deed, whether consciously or unconsciously.
And make me worthy to partake without condemnation of Thy most pure Mysteries, for the remission of sins and unto life everlasting.
Of Thy Mystical Supper, O Son of God, accept me today as a communicant. For I will not speak of Thy Mystery to Thine enemies, neither like Judas will I give Thee a kiss; but like the thief will I confess Thee: “Remember me, O Lord, in Thy Kingdom.”
May the communion of Thy Holy Mysteries be neither to my judgment, nor to my condemnation, 0 Lord, but to the healing of soul and body.
This prayer is actually said everytime before we do take the sacraments through the year, so it’s one of the most-important prayers in our Orthodox Church life.
The Holy Communion establishment is also an act of remembrance a of the Lord’s suffering for the remission of our sins according to his commandment.
One major difference between Orthodoxy and Protestanism concerning Eucharist is that we orthodox believe that by taking the sacraments, we do receive the Most-holy flesh and blood of Christ and through his blood and flesh, the damage sin has created in our hearts, minds and souls (which is forgiven by God in the the mystery of the confessment) is being recovered completjely.