I've always been a big music person. Ever since I can remember, I've been playing music. Playing the guitar is my most recently acquired musical talent. After I left on my mission, I didn't have as easy access to guitar as I did back home. But when I was in my first area, I had a couple opportunities to play guitar again. I was real excited, then once I started picking and strumming, I realized that I had lost a lot of what I knew. Many songs that I used to play had vanished from my memory. I was devastated!
Our knowledge and testimony will dwindle if we stop nourishing it as well. We need to continually improve our talents and skills. Alma, a Book of Mormon prophet said, "...Let us nourish it with great care, that it may get root, that it may grow up, and bring forth fruit unto us...but if ye neglect [it], and take no thought for its nourishment, behold it will not get any root..." (Alma 32: 37-38). We must nourish the skills and talents that we have so that when we need to be an instrument in the Lords hand, we will be fine tuned and ready to play.
We need to continue to exercise those things in our life. If we slack off on them, then our knowledge and ability will diminish. And when that day comes, you will feel as I did when I picked up the guitar after a couple of months...devastated! So do the little things every day, practice what you preach, apply what you learn, and you will never lose it.