Today, Jesus responds to his contemporaries questions about the true meaning of marriage by underlining its indissolubility.
His answer, however, also provides the adequate foundation for Christians to respond to those whose stubborn hearts have made them seek to extend the definition of marriage to homosexual couples.
In taking marriage back to God's original plan, Jesus underlines four things relevant to why only one man and one woman can be joined in marriage:
1) «In the beginning, the Creator made them male and female» (Mt 19:4). Jesus teaches that there is great meaning to our masculinity and femininity in God's plan. To ignore it is to ignore who we are.
2) «Man has now to leave father and mother and be joined to his wife» (Mt 19:5). God's plan is not that a man leave his parents and cling to whomever he wishes, but to a wife.
3) «The two shall become one body» (Mt 19:5). This bodily union goes beyond the short-lived physical union that occurs in the act of making love. It points toward the lasting union that happens when man and woman, through making love, actually procreate a child who is the perduring marriage or union of their bodies. It is obvious that man and man, and woman and woman, cannot become one body in this way.
4) «Let no one separate what God has joined» (Mt 19:6). God himself has joined man and woman in marriage and whenever we try to divide what he has joined, we do so at our own and all of society's expense.
In his catecheses on Genesis, Pope John Paul II said: «In his answer to the Pharisees, Christ put forward to his interlocutors the Total vision of man, without which no adequate answer can be given to questions connected with marriage». Each of us is called to be the “echo” of this Word of God in our own day.