Summary: The call to purity must be iterated in this day if the people of God are to enjoy His power.
“Let marriage be held in honor among all, and let the marriage bed be undefiled, for God will judge the sexually immoral and adulterous.” 
Listening to contemporary sociologists, one would conclude that marriage is a dying institution. Actually, one need not listen to sociologists to draw such a negative conclusion—the incessant push to redefine marriage is indicative of a serious problem in our world. First, the push was to broaden the concept to permit same-sex marriage. The argument was that if two people loved one another, who were we to doubt their love? The concept of marriage was solely as an expression of the means by which one gratified his/her personal desires. Thus, whether we realised the transformation or not, marriage was redefined.
The natural fallout from this redefinition was as predictable as it was inevitable. If all that was required for marriage was an expression of love, then why couldn’t multiple individuals enter into marriage? And if multiple individuals could enter into marriage, who was to say that children should be kept from marriage? And if children could be permitted to enter into marriage, then why not animals? The concerns that were expressed by Justice Antonin Scalia in Lawrence v. Texas  are being realised today, and no moral arguments remain to delay the inevitable. Soon, the western nations will be indistinguishable from Sodom and Gomorrah.
The effort to redefine sexual morality is as old as sin itself. Such danger was apparently looming when the writer of the Letter to Hebrew Christians drafted the missive. As that unknown writer drew his letter to a conclusion, he pointedly addressed the threat in succinct fashion. The inclusion of this warning should not be seen as superfluous; rather, it arises from a constant danger for Christians. His cautionary statement serves as the basis for our study today.
LET MARRIAGE BE HELD IN HONOUR AMONG ALL. If marriage is to be held in honour, we must know what marriage is. In order to know what marriage is, we should ask Him who gave marriage to mankind what His intent was. Thus, we find ourselves directed to the first marriage. When God had completed creating the heavens and the earth, filling the earth with the various animal kinds, He created Adam. We read, “The LORD God formed the man of dust from the ground and breathed into his nostrils the breath of life, and the man became a living creature” [GENESIS 2:7].
The acme of God’s creation was man; the man was unique, though it appears that he didn’t realise his uniqueness. God revealed man’s unique character through a fascinating means. The account of that divine revelation is provided in GENESIS 2:18-20. “The LORD God said, ‘It is not good that the man should be alone; I will make him a helper fit for him.’ Now out of the ground the LORD God had formed every beast of the field and every bird of the heavens and brought them to the man to see what he would call them. And whatever the man called every living creature, that was its name. The man gave names to all livestock and to the birds of the heavens and to every beast of the field. But for Adam there was not found a helper fit for him.”
It seems apparent that when this task of naming all the animals was complete, man realised his uniqueness. As an aside, it is apparent from this account that man did not evolve from an ape; otherwise, Adam would have recognised a bond with the apes when he named them. Adam was made aware of his spiritual and intellectual uniqueness—and his aloneness. God had caused those animals nearest in “kind” to the man—the livestock, the birds of the heavens and all the beast of the field. Moreover, it would seem that Adam was aware that each animal had its mate. Thus, he knew he was alone.
God had stated, “It is not good that the man should be alone,” [GENESIS 2:18]; and the man now knew as well that his state was “not good.” God had pronounced a benediction at completion of each step of the creation process, saying that His work was “good.”  Ultimately, the Lord God pronounces His work as “very good” [GENESIS 1:31].
However, there was one aspect of creation that was “not good”; the lack of one who was man’s complement was “not good.” The statement that this deficit was “not good” was more a recognition by Adam than an “Oops!” from the LORD God. One should not imagine that God was suddenly forced to resort to “Plan B,” as though somehow he had forgotten something. Politicians demonstrate the Law of Unintended Consequences whenever they craft legislation without considering the consequences. Thus, we witness the sorry spectacle of Presidents forced to invoke executive action to remedy oversights or to avoid politically unpalatable aspects of signature legislation. However, that was not the case with God; God was creating desire in the man, permitting the man to realise his deficit.