The eighteenth chapter of Leviticus is chiefly occupied with forbidding the unlawful indulgence of the passions. The Nephite prophet, Alma, told his son that harlotry was "most abominable above all sins, save it be the shedding of innocent blood;" Alma 39, 5. Jesus told his Nephite disciples "It is better that ye should deny yourselves of these things, wherein ye will take up your cross, than that ye should be cast into hell;" 3 Nephi 12. 30.
In Doc. & Cov., the passages are numerous in which adultery is forbidden. The Lord has given much instruction to the Latter-day Saints concerning the intercourse of the sexes. They are required to keep themselves strictly within their marriage covenants.
From the sacred writings, it would appear that in all dispensations of the Priesthood, the laws regulating this matter have been substantially the same, and have been calculated to strictly guard the issues of life; that all those who would keep them might be "perfect in their generations."
If, on the one hand, what the Lord does is eternal, because he is an eternal and infinite being, then what man does of himself, he being finite, must be limited to this life. Therefore, it is necessary that man and wife, to be eternally united, should be married in the way God has appointed, and by a man whom he has authorized to act in his stead.
It would not be consistent with the character of God, as the spiritual and natural father of mankind, to have no law regulating the marriages of his children, that they might be crowned with the blessings of eternal life and increase.
The Lord brought Abraham forth abroad, "And said, Look now toward heaven, and tell the stars, if thou be able to number them: and he said unto him, So shall thy seed be;" Gen. 15. 5. This was a promise of infinite and eternal increase. If we could count the stars, and grasp infinitude, we might comprehend the result of the promise.
We find that the Lord confirmed blessings to Abraham, and to his seed, by recorded ordinance and covenant. For this reason it is not probable that a blessing of such magnitude, as the sealing upon man and wife the power of eternal increase, is an exception. Abraham, in his own record, translated by Joseph the Seer, says, "I sought for the blessings of the fathers, and the right whereunto I should be ordained to administer the same." One of these blessings was, "To be a father of many nations, a prince of peace;" P. of G. P., page 26.
Abraham understood that this right could only be bestowed by ordination, by one of the fathers who had received it from the fathers in regular descent from Adam. He states that this right was conferred upon him from the fathers, according to his desire. That this right included the authority to regulate the marriage relations, in the future generations of his children, is evident from the further statement, "I sought for mine appointment unto the Priesthood according to the appointment of God unto the fathers concerning the seed." That is, he sought for that especial authority in the Priesthood, through which he had obtained the power of eternal increase.
The priest's office was bestowed upon Aaron and his posterity forever, by ordinance and covenant; Exodus 40. 15. Could this have been the case unless his posterity was made an eternal heritage through the everlasting covenant of marriage? This power of uniting husband and wife by an everlasting covenant of marriage, and by that ordinance giving them an eternal right over their posterity, descended from Abraham through the fathers, until Israel, by transgression, forfeited the blessing.
From the sharpness with which the prophet Nathan reproved David, and the statement that the Lord had given him the wives of his master Saul; 2 Sam. 12. 1-12, it is probable that the prophet held this authority.