
This prayer comes from the Divine Liturgy of St. John Chrysostom and is said by the people, after the Our Father, just before they are to come up for Holy Communion:
PEOPLE: O Lord, I believe and profess that You are truly Christ, the Son of the living God, Who came into the World to save sinners, of whom I am the first. Accept me as a partaker of your mystical supper, O Son of God, for I will not reveal Your mysteries to our enemies, nor will I give you a kiss as did Judas, but like the thief will I confess to You.
Remember me, O Lord, when You shall come into Your kingdom.
Remember me, O Master, when You shall come into Your kingdom.
Remember me, O Holy One, when You shall come into Your kingdom.
May the partaking of your holy mysteries, O Lord, be not for my judgment, or condemnation, but for the healing of soul and body.
O Lord, I also believe and profess that this, which I am about to receive, is truly Your most precious Body and Your life-giving Blood, which, I pray, make me worthy to receive for the remission of all my sins and for life everlasting. Amen
O God, be merciful to me a sinner.
God, cleanse my sins and have mercy on me.
O Lord forgive me for I have sinned without number.