I've been teaching Hyrum the Articles of Faith and so I was pondering today what we mean when we say "We believe in God the Eternal Father, and in His Son, Jesus Christ, and in the Holy Ghost." If someone unfamiliar with the church were to ask me that, the first part of my answer would probably be "I believe that God exists."
But when I see someone struggling and say to that person, "I believe in you," their mere existence is the last thing I'm referring to. Now I can imagine a philosophy student who has been trained to doubt his own existence communicating something meaningful by saying "I believe you exist," but I think when most of us use the phrase, we mean something a lot more.
I believe you will make the right decision. I believe you will endure. I believe you will fulfill your potential. I believe you are a good person. I trust you.
Trust. "We trust God the Eternal Father. We trust His Son Jesus Christ. We trust the Holy Ghost." We trust God's plan and His timetable. We trust that, though we are weak and vastly imperfect, Jesus can still make something better, even something glorious out of us because of who He is and His Atonement. We trust the promptings that the Holy Ghost gives us and follow them. We believe that we will be happy if we follow Them. We believe what They have said in the scriptures is true. When we do not know the way, we trust and rely on Them to see us through, because They are Way, the Truth, and the Life. We believe in Them.