By St. John the Prophet
Question 463: A Christ-loving layperson asked the same Old Man if one should reflect a great deal about the Sacred Mysteries, and whether a sinful person approaching these would be condemned as being unworthy.
When you enter the holies, pay attention and have no doubt that you are about to receive the Body and Blood of Christ; indeed, this is the truth. As for how this is the case, do not reflect on it too much. According to him who said: "Take, eat; for this is my body and blood" (Matt. 26:26-28), these were given to us for the forgiveness of our sins. One who believes this, we hope, will not be condemned.
Therefore, do not prevent yourself from approaching by judging yourself as being a sinner. Believe, rather, that a sinner who approaches the Savior is rendered worthy of the forgiveness of sins, in the manner that we encounter in Scripture those who approach him and hear the divine voice: "Your many sins are forgiven" (Lk. 7:47-48). Had that person been worthy of approaching him, he would not have had any sins. Yet, because he was a sinful man and a debtor, he received the forgiveness of his debts.
Again, listen to the words of the Lord: "I did not come to save the righteous, but sinners" (Mt. 9:13). And again: "Those who are well have no need of a physician, but only those who are sick" (Lk. 5:31). So regard yourself as being sinful and unwell, and approach him who alone can save the lost (cf. Lk. 19:10).
From The Letters of Saints Barsanuphios and John; translated by John Chryssavgis.