A person could ask, "which solitary verse of Scripture contains the greatest message?" There are a lot of verses in the running. And I'm sure not everyone would agree with me. But in my opinion I believe the answer is Mosiah 3:19.
"For the natural man is an enemy to God, and has been from the fall of Adam, and will be, forever and ever, unless he yields to the enticings of the Holy Spirit, and putteth off the natural man and becometh a saint through the atonement of Christ the Lord, and becometh as a child, submissive, meek, humble, patient, full of love, willing to submit to all things which the Lord seeth fit to inflict upon him, even as a child doth submit to his father."
This verse gives several important messages. Firstly it tells us that even though as a natural man we will sin and would be cut off forever, we can listen to the Holy Spirit, and put off the natural man. In other words we are not doomed to sin, as so many would try to claim. What a wonderful message. I can actually live a righteous life! I can put off sin, and never sin again. To a person such as myself, who was brought up a Protestant doomed to sin, this is just so wonderful. It fills my heart with joy. I can live a clean life, in harmony with eternal laws of love and life.
It tells me that I can be guided as to what is good and bad by the Holy Spirit. Again this message is just so amazing to me. I can have communication with the heavens. I need not remain in ignorance, as I had come to believe from my heritage. And I can be completely informed of what to do, and what not to do.
Not only don't I have to sin anymore but it tells my that my past sins can be removed by Jesus Christ, so that I need not wear them anymore. I can become a Saint (Greek equivalent to Hebrew word used relative to the sacrific - without spot or blemish - a pure person).
It states that we can become as a child in a spiritual way. We not only needn't sin, but we can, in fact, become sanctified people, full of all the most wonderful virtues in all eternity. How many people have I heard try to tell me I can't be perfect (let alone sanctified), or not in this life?
I used to hear people go on about how great King Benjamin's address was and couldn't see it at the time. My opinion has done a reverse on that one. And this verse sums it all up, IMO.