The problem of divorce
3 `Some Pharisees came to him to test him. They asked, “Is it lawful for a man to divorce his wife for any and every reason?”
4 “Haven’t you read,” he replied, “that at the beginning the Creator ‘made them male and female,’[a] 5 and said, ‘For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh’[b]? 6 So they are no longer two, but one flesh. Therefore what God has joined together, let no one separate.”
7 “Why then,” they asked, “did Moses command that a man give his wife a certificate of divorce and send her away?”
8 Jesus replied, “Moses permitted you to divorce your wives because your hearts were hard. But it was not this way from the beginning. 9 I tell you that anyone who divorces his wife, except for sexual immorality, and marries another woman commits adultery.”
10 The disciples said to him, “If this is the situation between a husband and wife, it is better not to marry.”
11 Jesus replied, “Not everyone can accept this word, but only those to whom it has been given. 12 For there are eunuchs who were born that way, and there are eunuchs who have been made eunuchs by others—and there are those who choose to live like eunuchs for the sake of the kingdom of heaven. The one who can accept this should accept it.”`
Adultery
Herma, The shepherd, Command IV – 29, 4-11, in Church Fathers and Writers (1979), vol. 1, p. 301-302
`Sir, I asked him, but if the woman after she had been left she repents and wants to return to her husband, won`t she be received back?`
`If the man doesn`t receive her, he told me, he sins and commits a big one; who sins and repents must be received; but not for many times; for the servants of God there is only one repentance. Therefore for the repentance of his wife the man must not remarry. This thing is a duty for both, man and woman.
Adultery, he told me, it is not only when someone defiles his body, he commits adultery as well when he makes deeds like pagans. Therefore, if someone continues to make such deeds and doesn`t repent avoid that one and don`t live with him anymore; otherwise you partake his sin. That is why it was commanded to you to remain as you are, man or woman (I Corinthians 7, 40); for in such cases there may be repentance.
The shepherd continued, I don`t want with this to create an opportunity for committing this sin but to make the sinner sin no more. In what regards his sin from before there is the One who can heal him; for He is the One who reigns over everything.`
Saint John Chrysostom, Homilies at Matthew, Homily VII, VII, in Church Fathers and Writers (1994), vol. 23, p. 100
`The man should honor the woman as due to her` (I Corinthians 7, 3). How do you honor her when you insult her in what she has more precious and you give to the whores your body which belongs to her? You know that your body is hers. How do you honor her when you bring in the house dispute and conflict?`
Source: http://ziarullumina.ro