There was a harlot named Thais, so beautiful that for her sake many people impoverished themselves. Her lovers used always to be quarrelling, and several young men spilt their blood on her doorstep.

When Abba Paphnutius heard of it, he took a secular dress and a gold shilling, and set out to see her in one of the cities of Egypt. He gave her his gold shilling for the price of her sin; she accepted it, and said: "Let us go into the house." As he was about to lie on the bed, which was strewn with costly coverlets, he beckoned her and said: "If there is an inner room, let us go into it." She said: "There is an inner room. But if you are frightened of men, no one comes into this outer room. If you are frightened of God, you cannot escape his eye anywhere." To this the old man said: "Do you know about God?" She answered: "I know about God, and the kingdom of the next world, and the future torment for sinners." He said: "If you know this, why have you destroyed so many souls, and therefore will have to give account for theirs as well as your own?"

When Thais heard this, she fell down at Paphnutius' feet, weeping: and said: "Lay a penance upon me, father. I trust with your prayers to win forgiveness. Let me have three hours' grace, and I will come wherever you command and do whatever you tell me." When Abba Paphnutius had appointed her a place to meet, she collected all the presents she had won by her sins. She took them into the city square and publicly burnt them, crying: "Come, all you people who have sinned with me, see how I am burning your presents." The value of the pile was forty pounds.

When she had burnt it all, she went to the appointed place. He found for her a hermitage for maidens, and put her in a little cell. He sealed the door, and left a little window through which she could receive food, and told the sisters of the convent to bring her a little bread and water every day. When Paphnutius had sealed the door and was going away, Thais said to him: "Where, father, would you have me pour my water?" And he said: "In the cell, you are worthy." Then she asked him how to pray to God. He said: "You are not worthy to have God's name on your lips, nor to stretch out your hands towards heaven; for your lips are full of wickedness and your hands polluted. You must simply sit down, look towards the east, and say this prayer again and again: 'Thou who hast fashioned me, have mercy upon me.'"

After she had been shut there for three years, Abba Paphnutius was moved with sympathy, and went to see Abba Antony, to ask him whether God had forgiven her sins or not. Abba Antony, learning all the circumstances, summoned his disciples and told them to watch all night, and persevere in earnest prayer that God would declare to one of them the answer for which Abba Paphnutius had come. They all went apart, and prayed continually: and Abba Paul, the chief disciple of Saint Antony, suddenly saw a bed in heaven covered with precious coverlets, and guarded by three maidens whose faces shone. Paul said to himself: "This is the gift of none but my father Antony." And a voice came to him: "It is not the gift of your father Antony, but of the harlot Thais."

Abba Paul told what he had seen: and Abba Paphnutius recognized the will of God, returned to the hermitage where Thais was shut, and broke the seals on the door. She asked him to let her stay shut in. But he opened the door, and said: "Come out, for God has forgiven your sins." She answered: "I call God to witness that from the time I came here I have kept my sins in my mind's eye like a burden, and I have kept weeping at the sight of them." Abba Paphnutius said: "God has forgiven you, not for your penitence, but because you always kept in your mind the thought of your sins." And he brought her out: and she lived for only fifteen days, and died in peace.