As a missionary i have learned a lot of things about the 'witness' of the Spirit. It teaching me truth as i read and pray, learning the Gospel of the Lord Jesus Christ. I am so grateful for the testifying power of the Spirit, that it lifts me and helps me to know of a surety that the things i am teaching are true.
The Book of Mormon has been a key principle in my understanding of the witness of the Spirit. As i have read and pondered over it, i have learned to recognize the still small voice much easier. The Book of Mormon is where the foundations of my testimony are rooted. As i finished reading the Book of Mormon for the first time as a full-time missionary, i felt something different from the times i had read it before. It just seemed so REAL and applicable, there was a special spirit in the apartment as i knelt and asked Heavenly Father to re-confirm my testimony of it. And now every time i read it i feel that same sweet Spirit, teaching me the truth of the words written.
My testimony of the Book of the Restoration has been a key point in learning the 'witness' of the Spirit, and knowing that Jesus Christ is my Savior and Redeemer. It has help me come to know Him on a personal level, and given me an understanding that He is real, that He lives, and He loves us. That through Him my mistakes can be taken away. I have a strong testimony that if you want to know truth, to listen for the Spirit as you ask.
Moroni 10:4 And when ye shall receive these things, I would exhort you that ye would aask God, the Eternal Father, in the name of Christ, if these things are not btrue; and if ye shall ask with a csincere heart, with dreal intent, having efaith in Christ, he will fmanifest the gtruth of it unto you, by the power of the Holy Ghost.