D&C 132

Probably one of the more misunderstood by some saints is -

Verily, verily, I say unto you, if a man marry a wife according to my word, and they are sealed by the Holy Spirit of promise, according to mine appointment, and he or she shall commit any sin or transgression of the new and everlasting covenant whatever, and all manner of blasphemies, and if they commit no murder wherein they shed innocent blood, yet they shall come forth in the first resurrection, and enter into their exaltation; but they shall be destroyed in the flesh, and shall be delivered unto the buffetings of Satan unto the day of redemption, saith the Lord God.
(Doctrine and Covenants Section 132:26)

Some individuals believe by this verse alone that they only have to be married in the temple to be guaranteed exaltation. Of course, no other scripture supports that idea but many to the contrary. Like many other verses in scripture, we have to combine the Lord's words to get the entire meaning.

First of all to be sealed by the Holy Spirit of Promise suggests being sealed by the second comforter or being sealed at the point when the Holy Ghost is really ratifying that an individual and in this case a couple that have lived and obeyed all covenants in such a manner that the persons callings and elections are made sure. Or they a guaranteed unto to exaltation. I don't know any personally that has been so valiant that they have received such a guarantee. I believe that is what the purpose or emphasis of these words is not necessarily being married in the temple, but in addition to being married in the temple, being sealed by the Holy Spirit of Promise. Which of course can be broken through disobedience.

Elder Bruce R. McConkie said -

Making one’s calling and election sure comes after and grows out of celestial marriage. Eternal life does not and cannot exist for a man or a woman alone, because in its very nature it consists of the continuation of the family unit in eternity. Thus the revelation on marriage speaks both of celestial marriage (in which the conditional promises of eternal life are given) and of making one’s calling and election sure (in which the unconditional promises of eternal life are given) in one and the same sentence—which sentence also says that those who commit sins (except ‘murder whereby to shed innocent blood’) after being sealed up unto eternal life shall still gain exaltation. This is the language: ‘Then’—that is, after their calling and election has been made sure—[D&C 132:19–20 cited].

Then the revelation [D&C 132:26] speaks of that obedience out of which eternal life grows, and still speaking both of celestial marriage and of making one’s calling and election sure says: ‘Verily, verily, I say unto you, if a man marry a wife according to my word, and they are sealed by the Holy Spirit of promise, according to mine appointment’—that is, if they are both married and have their calling and election made sure . . . ‘they shall come forth in the first resurrection and enter into their exaltation.’” (Doctrinal New Testament Commentary, 3:343–44.)
“What if those whose calling and election has been made sure thereafter commit grievous sins? Suppose they backslide and walk in the ways of wickedness? Or fight the truth and rebel against God—what then?

That all men commit sin, before and after baptism, and for that matter, before and after their calling and election is made sure, is self-evident. There has been only one Sinless One—the Lord Jesus who was God’s own Son.

Thus in the revelation announcing the setting up of the restored church in this day, the Lord says: ‘There is a possibility that man may fall from grace and depart from the living God; Therefore let the church take heed and pray always, lest they fall into temptation; Yea, and even let those who are sanctified take heed also.’ (D. & C. 20:32–34.)

The prophets and apostles from Adam and Enoch down, and all men, whether cleansed and sanctified from sin or not, are yet subject to and do in fact commit sin. This is the case even after men have seen the visions of eternity and been sealed by that Holy Spirit of Promise which makes their calling and election sure. Since these chosen ones have the sure promise of eternal life, and since ‘no unclean thing can enter into’ the Father’s ‘kingdom’ (3 Ne. 27:19), ‘or dwell in his presence’ (Moses 6:57), what of sins committed after being sealed up into eternal life?

Obviously the laws of repentance still apply, and the more enlightened a person is, the more he seeks the gift of repentance, and the harder he strives to free himself from sin as often as he falls short of the divine will and becomes subject in any degree to the Master of Sin who is Lucifer. It follows that the sins of the godfearing and the righteous are continually remitted because they repent and seek the Lord anew every day and every hour.

And as a matter of fact, the added blessing of having one’s calling and election made sure is itself an encouragement to avoid sin and a hedge against its further commission. By that long course of obedience and trial which enabled them to gain so great a blessing the sanctified saints have charted a course and developed a pattern of living which avoids sin and encourages righteousness. Thus the Lord said: ‘I give unto you Hyrum Smith to be a patriarch unto you, to hold the sealing blessings of my church, even the Holy Spirit of promise, whereby ye are sealed up unto the day of redemption, that ye may not fall notwithstanding the hour of temptation that may come upon you. (D. & C. 124:124.)

But suppose such persons become disaffected and the spirit of repentance leaves them—which is a seldom and an almost unheard of eventuality—still, what then? The answer is—and the revelations and teachings of the Prophet Joseph Smith so recite!—they must then pay the penalty of their own sins, for the blood of Christ will not cleanse them. Or if they commit murder or adultery, they lose their promised inheritance because these sins are exempt from the sealing promises. Or if they commit the unpardonable sin, they become sons of perdition.” (Doctrinal New Testament Commentary, 3:342–43.)