Правило 19 Святых Апостолов

Anyone who had two sisters or a niece in marriage cannot be in the clergy. (Trul. 26, 54; Neokes. 2; Basil the Great. 23, 78, 87; Theophila Alex. 5). This rule is based on the prescriptions of Holy Scripture (Lev. 18:7–14, 20:11–21; Matt. 14:4, 22:24; Mark 12:19), and therefore stems from divine law. Explaining the instructions of Holy Scripture, it in the form of a law prohibits the admission into the clergy of someone who, having previously had one sister as a wife, after her death took another sister, or someone who married the daughter of his brother or sister. As we will see in the interpretation of the 54th rule of the Council of Trullo and the 5th rule of Theophilus of Alexandria, such marriages were considered illegal in themselves, and were generally prohibited for the laity, the less such marriages could be tolerated among clergy. Taking into account the time of publication of this rule, one must assume that it, like many other Ap. rules, meant newly baptized pagans who, having entered into such marriages as pagans, remained in such illegal marriages for some time after baptism; but if someone, having accepted baptism, left an illegal marriage concluded in paganism, then he could freely enter the clergy, because the sin of pagan life is erased by holy baptism 168. Note to this rule in the Russian Synodal edition of the rules (ed. 1862), p. 18. You might be interested in: