In a podcast we watched in my class "The Eternal Family," this is what it says about justification:
If a couple is not automatically sealed when they participate in the ordinance of marriage according to Elder Hales then what are the requirements beyond simply performing the ordinance? Elder McConkie explains that all gospel ordinances are made binding through the process of Justification.
“All covenants, contracts, bonds obligations, oaths, vows, performances, connections, associations, or expectations, [D&C 132] in which men must abide to be saved and exalted must be entered into and performed in righteousness so that the Holy Spirit can justify the candidate for salvation in what has been done. [Justification] is the Lord’s way of assuring that no unauthorized acts or ordinances are binding in the hereafter.” (Elder Bruce R. McConkie, Mormon Doctrine, p. 408)
To me, this makes me think of when you have to "justify your actions" to someone. "Why do you have to bring the frog home, son? Well mom, he wanted to come home. He will be sad if he doesn't get to stay with me."
In heaven, that won't work. If we haven't been baptized, or received temple ordinances, or a temple sealing, we can't approach the pearly gates and say "I couldn't do it. My family members would be sad if I left them. They wanted me to stay with them" and be a "candidate for salvation."
This is an interesting concept for me in that "the Holy Spirit can justify the candidate for salvation." It sounds to me like the Holy Ghost (Spirit) will talk to the Lord and say, in effect, "They did all you asked them to do. They made covenants, with those who had proper authority, and lived up to those covenants. They are worthy of salvation."
He will "justify" our actions to the Lord.
Isn't that cool!