Summary: A call for purity in marriage for Christians.
“Let marriage be held in honor among all, and let the marriage bed be undefiled, for God will judge the sexually immoral and adulterous.” 
Marriage is under assault in this day. I sincerely doubt that the assault is as successful as some might imagine; nevertheless, marriage is under a sustained and vigorous assault. The transformation of marriage is reflected in changes in family size and composition. Statistics Canada gives us some insight into the changes experienced within the typical Canadian family. In 1961, the average family comprised 3.9 people; by 2011, the average family comprised 2.9 people. In 2011, for the first time there were more people living alone in Canada than there were couples with children. In 2001, the most common type of family (almost 44 percent) was two parents and children under 24 years of age living together. By 2011, that figure had dropped to 40 percent; and more of those couples were not officially married. And in 2011, for the first time, for the first time, StatsCan tracked step-families, people with children from a previous marriage living in the same home. They found that about ten percent of Canadian children were living in some variation of that particular situation. 
Between the years of 1961 and 2011, significant changes took place in the data collected. The first year in which data was available for common-law unions was 1981. In 2001, same-sex common-law couples were counted for the first time; and in 2006, same-sex “married” couples were counted for the first time.  The transformation of the family has been significant during these five decades. During this same period, the share of married-couple families has decreased while the share of lone-parent families has increased. Not surprisingly, families and households have become smaller during these same decades. 
Throughout the past fifty years, and especially during the past two decades, marriage has been redefined through political fiat and in the popular understanding. This redefinition was inevitable when the purpose of marriage was no longer recognised. Tragically, those who should have spoken out to instruct the populace in the biblical basis for marriage were either unprepared or unwilling to risk their standing in the community. Consequently, through the silence of the pastorate, marriage is in danger of being lost to western culture. When that happens, we will enter into a new dark age from which we may well never recover.
LET MARRIAGE BE HELD IN HONOUR AMONG ALL — The verse gives two commands, emphasised with a warning. We ignore divine commands at our peril, for they do come with warnings from which there is no appeal. God has graciously blessed the west for so long that we tend to forget that He is holy. Because He is holy, we trifle with His commands at our own peril. God cannot ignore arrogance toward His holy commands; He shall hold us accountable.
It would be a mistake to say that marriage is held in honour among all. Even within the congregations of the faithful, it is difficult to say that marriage is held in honour by all. To a distressing degree, the churches of this day reflect society rather than providing direction within society. It is more truthful to say that the churches of this day are guided by culture rather than providing moral guidance within culture. Pastors are more sensitive to say what is popular than to speak the truth in love. Nowhere is this more evident than in speaking of marriage.
During the century when the New Testament was being written, the churches existed in a culture without moral constraint. There were constraints, but it is difficult to speak of the constraints on human relationships as moral or ethical according to biblical standards. Christians stood out because of the demands imposed by the Faith for purity. The necessity of emphasising moral and ethical standards is evident even from a casual reading of the New Testament. Consider just a few of the passages that give guidance to those who would follow the Christ.
“Be imitators of God, as beloved children. And walk in love, as Christ loved us and gave himself up for us, a fragrant offering and sacrifice to God.
“But sexual immorality and all impurity or covetousness must not even be named among you, as is proper among saints. Let there be no filthiness nor foolish talk nor crude joking, which are out of place, but instead let there be thanksgiving. For you may be sure of this, that everyone who is sexually immoral or impure, or who is covetous (that is, an idolater), has no inheritance in the kingdom of Christ and God. Let no one deceive you with empty words, for because of these things the wrath of God comes upon the sons of disobedience. Therefore, do not become partners with them; for at one time you were darkness, but now you are light in the Lord. Walk as children of light (for the fruit of light is found in all that is good and right and true), and try to discern what is pleasing to the Lord. Take no part in the unfruitful works of darkness, but instead expose them. For it is shameful even to speak of the things that they do in secret. But when anything is exposed by the light, it becomes visible, for anything that becomes visible is light. Therefore, it says,