How do weaknesses with pornography and other sexual issues become strong? How do weak things become strong in this case?
Before I answer your question about how we can be strengthened, I feel the need to clarify that sin and weakness are not the same thing. They are, however, both parts of our fallen nature.
I feel the need to emphasize the difference because you appear to be referencing Ether 12:27:
“And if men come unto me I will show unto them their weakness. I give unto men weakness that they may be humble; and my grace is sufficient for all men that humble themselves before me; for if they humble themselves before me, and have faith in me, then will I make weak things become strong unto them”
It is important to note that the Lord gives us weaknesses, but He does not give us sin. I understood your intent to mean the desire to give up sins like pornography and sexual sin, but the difficulty in doing so, similar to what an alcoholic may feel about getting sober: the spirit is willing but the flesh is weak. For that reason, I want to share a talk Elder Bednar gave to a BYU audience about the “stengthening and enabling power of the Atonement”.
He says we often talk about the cleansing power of the Atonement for sin, but we don’t appreciate the power of the Atonement to help us in other ways. I think those other ways apply to the “weakness” you are speaking of.
Elder Bednar said:
“If I were to emphasize one overarching point this morning, it would be this: I suspect that you and I are much more familiar with the nature of the redeeming power of the Atonement than we are with the enabling power of the Atonement. It is one thing to know that Jesus Christ came to earth to die for us. That is fundamental and foundational to the doctrine of Christ. But we also need to appreciate that the Lord desires, through His Atonement and by the power of the Holy Ghost, to live in us—not only to direct us but also to empower us. I think most of us know that when we do things wrong, when we need help to overcome the effects of sin in our lives, the Savior has paid the price and made it possible for us to be made clean through His redeeming power. Most of us clearly understand that the Atonement is for sinners. I am not so sure, however, that we know and understand that the Atonement is also for saints—for good men and women who are obedient and worthy and conscientious and who are striving to become better and serve more faithfully. I frankly do not think many of us “get it” concerning this enabling and strengthening aspect of the Atonement, and I wonder if we mistakenly believe we must make the journey from good to better and become a saint all by ourselves through sheer grit, willpower, and discipline, and with our obviously limited capacities.”
I believe an unfortunate aspect of sin is the belief that we must now overcome our sins before we can return to Christ. But that is one of Satan’s most powerful lies. Satan wants to isolate you, to make you think you have to do the work on your own. But he knows that is impossible!
We cannot overcome our sins and/or weaknesses without the Savior’s help. Christ wants us to come to Him with our sins and weaknesses, He wants to help us overcome them. We say, “Oh no! I couldn’t go to Christ yet, I’m not worthy.” Remember when Christ asked to wash Peter’s feet and Peter strongly objected. He didn’t feel worthy to have Christ wash His feet, just as sometimes we do not feel worthy to come to the Lord with our sins. But note what the Savior said to Peter, “If I wash thee not, thou hast no part with me.” John 13:8
What He said to Peter, He says to all of us. Let his Atonement work in your life…not only to cleanse and forgive your sins, but to strengthen and enable you to overcome them. And when you have overcome your sins, with His help, then continue to draw on the power of the Atonement to overcome the natural man.
Our strength comes from turning to Christ in our weakness and sin.
P.S. You might also find this website helpful: Overcoming Pornography