For the past 2,000 years, the Catholic Church has consistently taught that marriage is permanent, exclusive and fruitful (Catechism of the Catholic Church, 1603-1605). In addition, the Church has taught that divorce (from a valid marriage) and remarriage is committing adultery (Catechism of the Catholic Church, 2384). Many want the Church to change its teaching so that the divorced and remarried can receive Communion. However, the Church does not have the authority to change God’s design for marriage as revealed in sacred Scripture, taught by the early Church Fathers and interpreted by the Magisterium.
The early Church Fathers were unanimous in their teaching regarding the permanence or indissolubility of marriage and the moral implications of divorce and remarriage. Simply stated a divorced person who remarried while his or her spouse was living committed adultery and lived in a perpetual state of mortal sin.
The Shepherd of Hermas was one of the most popular books produced in the early Church, and for a time it was frequently quoted and regarded as inspired. Hermas was the brother of Pius, bishop of Rome. He called divorce and remarriage adultery:
What then shall the husband do, if the wife continue in this disposition [adultery]? Let him divorce her, and let the husband remain single. But if he divorce his wife and marry another, he too commits adultery. (Shepherd 4:1:6 [A.D. 80])
St. Clement of Alexandria was a Christian theologian who taught at the Catechetical School of Alexandria. A convert to Christianity, he was an educated man who was familiar with classical Greek philosophy and literature. St. Clement, as other Church fathers, follows the counsel of Scripture on divorce and remarriage:
That Scripture counsels marriage, however, and never allows any release from the union is expressly contained in the law: “You shall not divorce a wife, except for reason of immorality.” And it regards as adultery the marriage of a spouse, while the one from whom a separation was made is still alive. “Whoever takes a divorced woman as wife commits adultery,” it says; for “if anyone divorce his wife, he debauches her”; that is, he compels her to commit adultery. And not only does he that divorces her become the cause of this, but also he that takes the woman and gives her the opportunity of sinning; for if he did not take her, she would return to her husband. (Miscellanies 2:23:145:3 [A.D. 208])
Origen lived through a tempestuous period of the Christian Church, when persecution was wide-spread and little or no doctrinal consensus existed among the various regional churches. He also called divorce and remarriage adultery, but included a stipulation about the death of the former spouse:
Just as a woman is an adulteress, even though she seems to be married to a man, while a former husband yet lives, so also the man who seems to marry her [and] who has been divorced does not marry her, but, according to the declaration of our Savior, he commits adultery with her. (Commentaries on Matthew 14:24 [A.D. 248])
St. Ambrose, Bishop of Milan, said to not even seek a divorce:
No one is permitted to know a woman other than his wife. The marital right is given you for this reason: lest you fall into the snare and sin with a strange woman. “If you are bound to a wife do not seek a divorce”; for you are not permitted, while your wife lives, to marry another. (Abraham 1:7:59 [A.D. 387])
Archbishop Gerhard Ludwig Müller, Prefect of the Congregation for the Doctrine of the Faith says the unanimous teaching of the Fathers was based on the words of Jesus.
For the Fathers, the biblical precepts on the subject are binding. They reject the State’s divorce laws as incompatible with the teaching of Jesus. The Church of the Fathers rejected divorce and remarriage, and did so out of obedience to the Gospel. On this question, the Fathers’ testimony is unanimous.
The Fathers based their teaching on Jesus’ words in the Gospels: “Every one who divorces his wife and marries another commits adultery, and he who marries a woman divorced from her husband commits adultery” (Lk 16:18, cf Mk 10:11–12).
To divorce and remarry is to commit the mortal sin of adultery. Scripture says, “Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived; neither fornicators nor idolaters nor adulterers…will inherit the kingdom of God” (1 Cor 6:9-10).
When speaking of the indissolubility of marriage, the Fathers also referenced St. Paul’s teaching in Ephesians 5:25-27 which exhorts husbands to love their wives “even as Christ loved the church and handed himself over for her to sanctify her, cleansing her by the bath of water with the word, that he might present to himself the church in splendor, without spot or wrinkle or any such thing, that she might be holy and without blemish.”
St. Ignatius of Antioch said, “Tell my sisters to love the Lord and to be satisfied with their husbands in flesh and spirit. In the same way tell my brothers in the name of Jesus Christ to love their wives as the Lord does the Church.” (emphasis added)
Another Church Father, St. Augustine identified indissolubility as one of the three “goods” of marriage. In Catholic Sexual Ethics: A Summary, Explanation and Defense, Lawler, Boyle and May state that it is this indissoluble unity of husband and wife “which constitutes the reality of marriage…Indissolubility imposes a moral obligation on spouses not to attempt another marriage as long as their partner is alive. This obligation holds even if it is necessary to separate, even if one is deserted.”
Lawler, Boyle and May go on to explain why the bond of marriage cannot be broken.
The bond of marriage is a reality, not a matter of human convention, and when that bond is created in the life of two Christians, it simply cannot be broken. This bond is intended by God to symbolize the love of Christ for his Church, and as a sacrament of the new covenant it partakes of that divine and human love. And that love cannot be broken by any power in the universe…A spouse can no more become an ex-spouse than a father can become an ex-father, or a mother an ex-mother. They may cease to love each other as spouses should, but they are spouses until death.
Cardinal Joseph Ratzinger, who became Pope Benedict XVI, explained why spouses who divorce and remarry cannot receive the sacraments:
Marriage is not simply about the relationship of two people to God, it is also a reality of the Church, a sacrament, and it is not for the individuals concerned to decide on its validity, but rather for the Church, into which the individuals are incorporated by faith and baptism. “If the prior marriage of two divorced and remarried members of the faithful was valid, under no circumstances can their new union be considered lawful, and therefore reception of the sacraments is intrinsically impossible. The conscience of the individual is bound to this norm without exception” (Cardinal Joseph Ratzinger, “The Pastoral approach to marriage must be founded on truth” L’Osservatore Romano, English edition, 7 December 2011, p. 4) (emphasis added)
While this may seem harsh, God knows what will make us truly happy. He gives us His commands as a blessing. The men and women wounded from the failed sexual revolution are all around us. God has a better plan: chastity before marriage, and marriage between one man and one woman, for life. True joy, fulfillment and happiness are found in living out God’s plan for human sexuality in the context of a lifelong, committed and fruitful marriage.
Just as the early Church Fathers courageously proclaimed Christ’s teaching on the indissolubility of marriage in the midst of the Greco-Roman culture, which allowed for easy divorce and remarriage, so must the Catholic Church continue to proclaim the truth, beauty and goodness of God’s plan for marriage in today’s easy-divorce culture.
 Catholic Answers Magazine, “The Permanence of Matrimony,” http://www.catholic.com/tracts/the-permanence-of-matrimony (accessed December 7, 2016).
 Gerhard Ludwig Müller, Testimony to the Power of Grace: On the Indissolubility of Marriage and the Debate Concerning the Civilly Remarried and the Sacraments, http://www.vatican.va/roman_curia/congregations/cfaith/muller/rc_con_cfaith_20131023_divorziati-risposati-sacramenti_en.html (accessed December 15, 2016).
 John R. Willis, SJ, ed., The Teachings of the Church Fathers, (San Francisco: Ignatius Press, 2002), p. 438.
 Ronald Lawler, OFM Cap., Joseph Boyle, Jr., and William E. May, Catholic Sexual Ethics: A summary, Explanation, & Defense, (Huntington: Our Sunday Visitor, Inc., 1996), p. 138.