The following story was extracted from the "The Great Synaxaristes of the Orthodox Church", the life of Saint Basil.
In Caesarea there was a prince named Proterios, who was both God fearing and very rich. He had a fifteen-year-old daughter, his only child, who was beautiful in appearance. So, what did the crafty devil, the enemy of virginity, conspire? He kindled a wicked lust in one of the prince's slaves, constraining that one to find any way to make the maiden his wife. Since he was unable to succeed in realizing his desire, he went to solicit a wizard of the idolaters, a minister of the devil, and said to him, "If thou shouldest turn around the heart of my master's daughter, so that she would be in love with me, and take me as her husband, I am willing to become thy slave, and whatsoever thou dost wish I shall give to thee." The magician then made this answer to the slave, "If thou wilt deny thy Christ in a document, I am willing to accomplish that which though desirest." The lamentable slave answered, "I deny the Christ by both word and written record enough to bring my will to pass." The magician then said to him, "I intend to give thee a letter. At midnight thou art to go to the cemetery of the idol worshipers where, upon invoking the demons, thou shall lift this letter into the air. Then the demons should come. They will take hold of thee, and conduct thee to their leader; and there shall come to pass that which thou dost yearn after." The magician went on writing: "Inasmuch as thou art my lord and master, it is fitting that I serve thy desire to turn about the Christians from the Faith of Christ, that they might believe in thee. For this reason, I am sending forth this youth, who is consumed by passionate love. I beseech thee to bring about his will that I too might enjoy splendor and dignity among the people, thereby causing them to hasten together to me."
After he wrote it, he handed it over to the beguiled youth. That wretched slave, according to the magician's command, stood upon the tomb of one idolater at the appointed hour. He then called upon the demons, flinging the letter. Straightway, they appeared before him and said, "If thou wilt have what thou desirest take place, keep on following us." They conveyed him to that place where the profane devil was sitting upon a high seat, encircled by other demons. Having read the writing of the wizard, he said to the youth, "Believest thou in me?" that one answered, "Yea, I believe." Again the devil queried, "Dost thou deny the Christ?" The deluded youth responded, "Yea, I deny Him." The devil resumed speaking, saying, "An ungrateful lot are you Christians, because whenever a need should arise in your lives, then you come to me. Whenever it should come to pass that which you desire, you deny me and go to the Christ Who, since He loves mankind, receives you. But thou, deny in writing thy Faith and the Baptism, and write that thou shall accept to be punished eternally with me in the Day of Judgment; and then I shall minister to thee."
Then that miserable and gullible young man, having been blinded by lust, gave the foul creature the document of his denial of the Faith, even as the demon sought. After committing this reckless act, he returned to his master's house. Forthwith, the devil dispatched his minions to lure the maiden, so that she might desire the youth. After a certain number of days, that maiden, succumbed, and was compelled to cry out, "Either give me that slave as a husband, or else I wish to die!" Her parents, when they heard such desperate pleas, regularly and with increasing vehemence, and that she would hang herself, took advice from certain friends. They counseled it was better for what she longed for to take place, than for her to die wrongfully. With weeping and lamenting, the parents yielded, and the marriage was performed. Now after they were married, the young man never stepped into a church, neither would he commune, nor even make the sign of the Cross. This conduct was noticed by certain neighbors who said to his wife, "Know this well, that thy spouse is not a Christian." Therefore, one day, she said to her husband, "I have the ill-feeling that thou art not a Christian, since so many Sundays and feasts have passed, and thou dost not go into the church nor thou make the sign of the Cross. I however, thinking that thou art a Christian, agreed to marry thee. If then thou wilt refuse to go to church with me, I want to be separated from thee."
Then the sufferer, not being able any longer to keep hidden what he committed, came out with it, saying to her, "I, in order to make thee love me, denied Christ in writing. I cannot, then, enter into a church of the Christians, nor commune." When that unfortunate woman heard this doleful admission, she wept, wailed, and beat her breast because of the calamity, which had befallen her. Therefore, she hastened to Saint Basil and related the matter to him. Then the saint called the young man and questioned him concerning the incident. He, with tears, confessed the whole truth. At that time the saint asked the young man, "Dost thou wish to repent?" He answered, "O holy master, I do wish it; but I am unable, because I denied my Faith in a document." The saint responded, "Hearken to whatever I should tell thee." Continuing, he declared, "Do thou not give care on account of thy written confession; for repentance is yet powerful, even to render thy signature useless." The youth said, "My soul hangs on thy neck, holy master. Whatsoever thou shouldest command, I am willing to do." Then the saint enclosed the youth inside his own cell, and said to him, "Continue abiding here and praying and fasting for three days, and afterward I myself shall come to see thee."
Now the saint kept on praying and entreating, with fasting, for the sake of that man's salvation. After the third day, the holy hierarch came and asked him, "How art thou faring, my child?" The young man disclosed, "I find myself in great anguish, holy one of God, because I cannot endure the loud cries and thrashings of the devils, for they are holding my confession and warring against me, saying, "Regardless of how much thou toilest, thou shall not be able to lighten the weight, since we hold the letter which is in thine own handwriting." The Saint encouraged him, saying, "Cease fearing, child; only keep on believing, and thou shall be saved." After he pronounced these things, the saint also gave him bread and water; and again he immured him in the cell. After the passage of a certain number of days, again the saint went to him and asked him, "How is it with thee, child?" This time the youth answered, "Through thy holy prayers, well; because now I do not see the demons appearing before my eyes. I only hear their loud cries and threats from afar." And again, after the saint gave him food and prayed over him, he closed the door and departed.
When they completed forty days, again the saint went to him and inquired, "How art thou holding up, child?" That youth replied, "With thy prayer, very well, holy master. Now I do not even see the evil and ugly shadow of the demons, nor do I hear their cries. Above all, this night I beheld a vision that thou didst wrestle with the devil, and prevailed." Straightway, the holy man sent forth a message, ordering all the clergy and Christians to gather together into the Church. When all assembled, he appealed to them "My beloved children, let us all give thanks unto the Lord, for the lost sheep is found. But it is fitting that we also should labor, for the love of Christ, and keep vigil during this night, that He might show mercy to the creation fashioned by His hands." Having, therefore, kept vigil with psalms and the shedding of fervent tears, they were entreating God throughout the night. During the third hour of the day, the saint entered into the sanctuary to commence the Divine Liturgy.
While he was performing the divine service, the demons audaciously entered that holy precinct, in order to seize the youth. That youth then, panicking with fear, dashed to Saint Basil, and took hold of him, imploring, "Have mercy on me, servant of God, have mercy on me, because the demons have come! They wish to snatch me away!" Bravely, Saint Basil said to the demons, "O shameless and defiled creatures are you not satisfied with your own destruction, but have you come into the temple of God to carry off this man?" One of the demons gave answer to the hierarch, saying, "Thou didst wrong me, Basil. I did not go to him, but he, of his own will, came to me, and denied his Faith. Behold, the written record of his confession!" Undaunted, the saint replied. "Blessed be my God! These people are not willing to bring down their hands in prayer, unless thou shouldest give back the document." And having turned to the clergy, he bade them, "Raise up your hands to the heavens, and cry aloud with tears the 'Lord, have mercy.'" Standing before the people, the saint directed them also to repeat the same; and for a long time they supplicated, crying aloud, "Lord, have mercy." Behold, the document, bearing the youth's denial, was seen borne along in the air, until it came and lay in the saint's hands. After he received it, the holy hierarch offered up thanks to God. Saint Basil then asked the youth, "Dost thou recognize thy letter made with thine own hand?" He confirmed, "Yea, saint of God, this is it." The saint then shredded the document and went on celebrating the Divine Liturgy. After this event, the holy man admonished him and anointed him with Holy Chrism. He then handed him over to his wife. The couple returned to their house, glorifying and blessing the all-compassionate God.