People often refuse new truth because they can’t figure out how to believe it without letting go of something they already believe. The Lord said:
36 No man putteth a piece of a new garment upon an old; if otherwise, then both the new maketh a rent, and the piece that was taken out of the new agreeth not with the old.
37 And no man putteth new wine into old bottles; else the new wine will burst the bottles, and be spilled, and the bottles shall perish. (Luke 5)
The Lord was referring to how the Pharisees struggled to accept his teachings during his mortal ministry. The Pharisees and company not only had preconceived notions about the truth, they prided themselves on being ideological leaders of the people. Then Jesus came and told them they were blind leaders of the blind. Trying to teach them anew with old scriptures just didn’t work, because the people just couldn’t accept the possibility that they had it all wrong.
When higher truth is revealed, and we are confident that it comes from God, we must refit previously accepted truths into the new perspective given us by the Lord. If things do not fit, they ought to be removed. The old order is not amenable to new truth. You have to start fresh.
An example of letting go of lower truth in order to accept higher truth is given in Nephi, who firmly believed that killing someone was contrary to God’s law. He was told by God to kill. He was taught what principles define the finer edge between sin and righteous action when it comes to killing. He was introduced to a higher law which required him to let go of the lower law. Failing to accept that light and truth when it came would have led to many short-term negative consequences and the long-term negative consequence of his eternal damnation (or limitation) except and until he was willing to accept the higher law.
If you arrive at a new truth that does not fit in your present understanding of things, you should just keep trying to ask questions and seek new knowledge until everything is reconciled. When God commanded Abraham to sacrifice Isaac, he did not refuse. Eventually, he was taught exactly why this was necessary.
Lack of truth is not a result of it not being available—it is all around you, all the time. Every artificial boundary we place on putative truth limits the quantity of truth we receive. It seems each of us has a line in the sand where we say “God would never ask me to _.” We should recognize these arbitrary bounds for what they are. Instead of lauding our assumed superiority in moral judgment (which should be blatantly obvious due to our lack of spiritual fruit), we ought to recognize our sacred cows as evidence of a lack of trust in God. Trust in God’s character gives us prior belief of whatever he is going to teach us, no matter how outlandish it seems.
Perfect love removes all fear. If you truly love God, then seek to know him on his terms, holding nothing back. Only those who put everything they think they know about God on the altar can come to know him.
We can extend our capacity to accept new light and truth through penitent prayer and humility towards God. When we truly believe we know nothing, we are much more willing to accept new truth. When we are totally willing to let go of anything we think we know, we are much more willing to accept new truth.
When we refuse to dismiss anything out of hand (as John instructs us— “try the spirits” or test new truth to see its fruits), we are much more willing to accept new truth. When we refuse to dictate to God what is right and what is wrong, we are much more willing to accept new truth. When we realize that what was right before and what God might have inspired us to accept before could be superseded by something higher, we are much more willing to accept new truth. It is possible to come to the point where no truth pertaining to the Celestial, Terrestrial, or Telestial kingdom has power to derail you, despite the fact that you do not yet know them. This is when your calling and election is made sure, or rather this is what it means and what it takes.
Too often in life, we subscribe to the idea that we can, at some point, be “done.” We rest on the laurels of previous truth acquisition. When something becomes known and ordered, it is not a sign that it is done. Functionality does not imply completeness. Something good does not imply the nonexistence of something better. Truth does not confine you to a box; it gives you the confidence to explore everything you don't yet know, and test against what you think you do know. Much of the pain of hell comes from the surprise that everything you assumed was final is in actuality anything but.
Anyone willing to set up limits on the domain of truth will succeed only in limiting their own acquisition of it.