Faith in the Lord Jesus Christ is the first princple of the gospel as stated in the 4th article of faith. Just having faith isn't enough, it must be in the Lord Jesus Christ. One way that we can tell that faith is a fundemental requirement of the gospel, is that the dead also must be taught to have faith, as seen in D&C 138:32-34. Joseph B. Wirthlin teaches us that "Faith is not so much something we believe; faith is something we live." Thoughtout this life we need to learn to walk by faith and not by sight, 2 Corinthians 5:7.
The first scripture that I think of on faith is Alma 32:21 where Alma teaches us that "faith is not to have a perfect knowledge." A simiular scripture is, Hebrews 11:1 where Paul teaches us that "faith is the substance of things hoped for, the evidence of things not seen." Just having faith isn't enough, it must be in the Lord Jesus Christ. A talk that Dallin H. Oaks gave at a General Young Women Meeting is really good on this.
The scripture that inspired Joseph Smith to go to the grove and ask God which church to join, James 1:5-6, clearly states that God will answer our prayers, but only if we have faith in Him. The promise found in Moroni 10:4-5 that tell us how we can know the truefullness of the Book of Mormon clearly states that we must ask in faith.
Our faith will protect us from the powers of evil. When we put on the whole armour of God, the shield is fath, Ephesians 6:16. With faith we can quench the fiery darts of the wicked.
The Prophet Joseph said "It was by faith that the worlds were framed."
We need to have faith in the Lord and faith that we can hear and do His will. When Nephi's brothers didn't want to help him build a ship, he tell's them that "If God had commanded me to do all things I could do them," 1 Nephi 17:50-51. See also Moroni 7:33.
Faith gives us the power to do all things, Jacob 4:6-7 A little bit of fatih makes us so we can do great things, "faith as a grain of mustard seed," Luke 17:5.
Enoch had such great faith that he could defend the people of God against the armies of their enemies through the power of his word, Moses 7:13.
Enos's sins were swept away becaue of his faith in Christ, Enos 1:5-8. We are saved by grace through fatih, Ephesians 2:8.
President Hinckley tells us that we need faith to follow the Churh leader's counsel in the little things which are so important.
Before we can have faith in Christ we must first have someone to teach us about Him, Romans 10:14-15. Verse 15 talks about how "beautiful are the feet of them that preach the gospel of peace." We can't develop faith without first being taught the true gospel, D&C 88:118-119. We need to continue gaining knowledge both by study and by faith.
We need to work to increase our faith, but in reality having faith is one of the gifts of the Spirit, Moroni 10:11.
Alma tell us how we can increase or faith when he compares the transformation of faith into knowledge as the growth of a seed, Alma 32:26-34. The whole 11th chapter of Hebrews is on faith. Paul tells us of the great things that have happened in the past from the creation of the world through the works of Moses and the other prophets and tells us all these things were done by faith. Verses 33-35 sum up some of the woderful things that have and can be accomplished through the power of faith. In verse 4 Paul tells us that through faith we can know that our life is pleasing unto God. Verse 6 tells us that without faith it is imposible to please God. The twelfth chapter of Ether in the Book of Mormon also has much about faith and that all the wonderful events of the past happened through faith. Verse 6 tells us that we receive no witness until after the trial of our faith. Verse 12 tells us there can be no miracles without faith. Verse 19-21 tells us that if we have enough faith we can see God.
Richard G. Scott teaches us that we increase our faith by exercising the faith that we already have.
The story of the father with a son having a dumb and deaf spirit teaches us much about faith. Mark 9:17-29. First the father wants to know if Jesus has the power to heal his son. He thought that everthing depened on Jesus' power, but Jesus lets him know that his son can be healed only if he (the father) has enough faith. The father desperatly wants to have enough faith, but is unsure that his faith will be sufficient so crys out to Jesus for help. This teaches us that we can ask (pray) to have enough faith to meet the challenges that are required of us. Also the disciples later ask (verses 28-29), why they couldn't heal the boy and Jesus teaches them how they could increase their faith by fasting and prayer.
The story of Doubting Thomas shows us how easy it is to not have faith, yet how much the Lord expects us to have faith, John 20:24-29.
As we increase in faith addition things will be revealed to us. The Book of 3 Nephi only contains the lesser things that Jesus taught the people. These things are to try our faith, so that we can be prepared to someday receive the greater things, 3 Nephi 26:8-9. If we have faith as the brother of Jared, then we will see all the things that the brother of Jared saw. Ether 4:6-7. James teaches that faith alone isn't enough, it also takes works. Faith without works is dead, James 2:14-26. Verse 18 is the one that says "shew me thy faith without thy works, and I will shew thee my faith by my works." Verse 24 says "by works a man is justified, and not by faith only."