by St. Basil the Great
Canon 3. A deacon who commits fornication after his appointment to the diaconate is to be deposed. But, after he has been rejected and ranked among the laity, he is not to be excluded from communion. For there is an ancient canon that those who have fallen from their degree are to be subjected to this kind of punishment alone.
Canon 6. The fornication of canonical persons is not to be reckoned as wedlock, and their union is to be completely dissolved, for this is both profitable for the security of the Church and will prevent the heretics from having a ground of attack against us, as though we induced men to join us by the attraction of liberty to sin. (1st Canonical Letter, Epistle 188)
Canon 26. Fornication is not wedlock, nor yet the beginning of wedlock. Wherefore it is best, if possible, to put asunder those who are united in fornication. If they are set on cohabitation, let them admit the penalty of fornication. Let them be allowed to live together, lest a worse thing happen. (2nd Canonical Letter, Epistle 199)
Canon 59. The fornicator will not be admitted to participation in the sacrament for seven years; weeping two, hearing two, kneeling two, and standing one: in the eighth he will be received into communion.
Canon 69. The Reader who has intercourse with his betrothed before marriage, shall be allowed to read after a year’s suspension, remaining without advancement. If he has had secret intercourse without betrothal, he shall be deposed from his ministry. So too the minister. (3rd Canonical Letter, Epistle 217)