Those who would increase their faith must be able to handle all of the most difficult things in life. Moreover, they must do it willingly and with joy in their hearts. The Lord will inevitably require the most difficult tasks and sacrifices of them. He knows the heart, and knows how to test His children, and He will take them to the limit in all things. They must be "willing to submit to all things which the Lord seeth fit to inflict upon [them], even as a child doth submit to his father." (Mosiah 3:19)
Sacrifice everything
The essence of growing in the Gospel is sacrifice. The word "worship" is synonymous with sacrifice. Joseph Smith stated, "The faith necessary unto the enjoyment of life and salvation never could be obtained without the sacrifice of all earthly things." (Lectures on Faith, Lecture Sixth) The requirement is "all earthly things." All means all and all is all all means. Jesus said that even your own family must be sacrificed. "He that loveth father or mother more than me is not worthy of me: and he that loveth son or daughter more than me is not worthy of me." (Matthew 10:37) Nothing you possess is out of the reach of God. All of it must be sacrificed, or we cannot come to Him.
Those who make a covenant with the Lord are often surprised by how difficult these sacrifices are. Many describe what happens next as being akin to Job. They lose wealth, health, family, friends, lands, houses, and businesses. As these things are lost, they must sit still and trust in the Lord. They do not charge God foolishly. Instead they say as Job, "For I know that my redeemer liveth, and that he shall stand at the latter day upon the earth: And though after my skin worms destroy this body, yet in my flesh shall I see God:" (Job 19:25-26) It is hard to sacrifice to the Lord.
Stand alone
No matter what everyone else is doing, a Christian must be able to stand alone, even at the peril of his life. Many have been rejected by their closest friends and relatives in order to follow Christ. They are often mocked and persecuted for believing differently. My teenage son told me, "How can you be happy when your own wife and children hate you for what you believe?" It is hard to be all alone in the world.
Walk in darkness
Faith is the belief in things which we cannot see. To walk in faith is paradoxically to walk in both darkness and light. The darkness is in the world, doing things that make no sense to the outside observer such as keeping the commandments of God. The light is the Light of Christ, or a knowledge of things that are only spiritually understood. "But the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned." (1 Corinthians 2:14) All of the "natural men" see Christians as idiots, wasting their lives on some pie-in-the-sky hope that they cannot even explain. Even Paul noted this paradox: "If in this life only we have hope in Christ, we are of all men most miserable." (1 Corinthians 15:19) It's hard to walk by faith.
Move ahead in spite of fear
A blind person without a cane or help is walking in fear. Every step could bring him into the pit, over a cliff, or some other danger. Likewise, walking by faith is a fearsome thing. We are most often not told why we must do things. The Lord simply commands and we obey. Sometimes it's painful. Often it's hard. Always we must trust that it is for our own benefit. Because of this we put aside our fear and move ahead with courage in our hearts. It is hard to be obedient.
Humble yourself
When we acknowledge the omniscience of God we are at the same time recognizing our own ignorance. Based on this we humble ourselves and live "by every word that proceedeth out of the mouth of God." (Matthew 4:4) We give up all things we think and want. We give up everything we have been taught by our parents, school and society, and try to learn the ways of God. "For my thoughts are not your thoughts, neither are your ways my ways, saith the Lord. For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts." (Isaiah 55:8-9) It is hard to be humble.
Forgive everyone
Jesus commanded His disciples that they go against their very natures, giving up their own sense of justice. Those who would be followers of Christ must not hold a grudge, seek revenge, or even seek justice on those who hurt them. There is no amount of pain, big or small, that we don't forgive. Even when we are repeatedly injured, to seventy times seven, we are to forgive. A Christian desires forgiveness for himself so he must let go of all justice for others as well. It's hard to endure injustice.
Love your enemies
What's more, a Christian must even have to love those who hate, despise, reject, use, or persecute them. "But I say unto you, Love your enemies, bless them that curse you, do good to them that hate you, and pray for them which despitefully use you, and persecute you." (Matthew 5:44) Forgiveness is not only a matter of letting go of justice, it requires making a sacrifice to benefit those who have hurt us. A man who randomly shot children in a school, killing many Amish children, then shot and killed himself. The families of those children who had died took up a collection for the widow of the man who killed them. This is the very thing it takes to become a child of Christ. It's hard to love your enemies.
Endure to the end
Christians cannot make a covenant with God and then not keep it. We must at all times be witnesses of Him until the end of our lives. Those who quit have no benefit. It's a constant battle. There is no rest. At the end of his life, Paul had this to say to Timothy, "I have fought a good fight, I have finished my course, I have kept the faith." (2 Timothy 4:7) He had endured to the end of his life. "Endure" is a double entendre: to continue, and to withstand. It is hard to endure to the end.
Growing up
Growth is hard. All of these difficulties that a Christian endures help us to grow. We grow up in the knowledge of God, coming to know Him. Paul indicated this in writing about charity. "When I was a child, I spake as a child, I understood as a child, I thought as a child: but when I became a man, I put away childish things." (1 Corinthians 13:11) "Putting away childish things" is not easy, but there are benefits. We are endowed with gifts of knowledge, wisdom, peace, love, and joy. We can receive the comforting Spirit. We can have "the peace of God, which passeth all understanding." (Philippians 4:7) Also, as we learn truth we are freed from the tyranny of sin. Ultimately, we come to know God, and life. "And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent." (John 17:3) Becoming a Christian is worth every effort and sacrifice -- and so much more! However the process of growing up is definitely not for the fainthearted.