Some Pharisees approached Jesus, and to test him they said, ‘Is it against the Law for a man to divorce his wife on any pretext whatever?’ He answered, ‘Have you not read that the creator from the beginning made them male and female and that he said: This is why a man must leave father and mother, and cling to his wife, and the two become one body? They are no longer two, therefore, but one body. So then, what God has united, man must not divide.’
They said to him, ‘Then why did Moses command that a writ of dismissal should be given in cases of divorce?’ ‘It was because you were so unteachable’ he said ‘that Moses allowed you to divorce your wives, but it was not like this from the beginning. Now I say this to you: the man who divorces his wife – I am not speaking of fornication – and marries another, is guilty of adultery.’
The disciples said to him, ‘If that is how things are between husband and wife, it is not advisable to marry.’ But he replied, ‘It is not everyone who can accept what I have said, but only those to whom it is granted. There are eunuchs born that way from their mother’s womb, there are eunuchs made so by men and there are eunuchs who have made themselves that way for the sake of the kingdom of heaven. Let anyone accept this who can.’
Source: Jerusalem Bible
Catechism of the Catholic Church
“Teacher, what must I do . . .?”
2052 “Teacher, what good deed must I do, to have eternal life?” To the young man who asked this question, Jesus answers first by invoking the necessity to recognize God as the “One there is who is good,” as the supreme Good and the source of all good. Then Jesus tells him: “If you would enter life, keep the commandments.” And he cites for his questioner the precepts that concern love of neighbor: “You shall not kill, You shall not commit adultery, You shall not steal, You shall not bear false witness, Honor your father and mother.” Finally Jesus sums up these commandments positively: “You shall love your neighbor as yourself.”
2053 To this first reply Jesus adds a second: “If you would be perfect, go, sell what you possess and give to the poor, and you will have treasure in heaven; and come, follow me.” This reply does not do away with the first: following Jesus Christ involves keeping the Commandments. The Law has not been abolished, but rather man is invited to rediscover it in the person of his Master who is its perfect fulfillment. In the three synoptic Gospels, Jesus’ call to the rich young man to follow him, in the obedience of a disciple and in the observance of the Commandments, is joined to the call to poverty and chastity. The evangelical counsels are inseparable from the Commandments.
2054 Jesus acknowledged the Ten Commandments, but he also showed the power of the Spirit at work in their letter. He preached a “righteousness [which] exceeds that of the scribes and Pharisees” as well as that of the Gentiles. He unfolded all the demands of the Commandments. “You have heard that it was said to the men of old, ‘You shall not kill.’ . . . But I say to you that every one who is angry with his brother shall be liable to judgment.”
2055 When someone asks him, “Which commandment in the Law is the greatest? Jesus replies: “You shall love the Lord your God with all your heart, and with all your soul, and with all your mind. This is the greatest and first commandment. And a second is like it: You shall love your neighbor as yourself. On these two commandments hang all the Law and the prophets.” The Decalogue must be interpreted in light of this twofold yet single commandment of love, the fullness of the Law:
The commandments: “You shall not commit adultery, You shall not kill, You shall not steal, You shall not covet,” and any other commandment, are summed up in this sentence: “You shall love your neighbor as yourself.” Love does no wrong to a neighbor; therefore love is the fulfilling of the law.