Doctrine and Covenants 15 and 16

 

Why is bringing souls unto Christ of great worth?

"Revelation given through Joseph Smith the Prophet to John Whitmer, at Fayette, New York, June 1829 (see the heading to section 14). The message is intimately and impressively personal in that the Lord tells of what was known only to John Whitmer and Himself. John Whitmer later became one of the Eight Witnesses to the Book of Mormon.

1–2, The Lord’s arm is over all the earth; 3–6, To preach the gospel and save souls is the thing of most worth.

1 Hearken, my servant John, and listen to the words of Jesus Christ, your Lord and your Redeemer.

2 For behold, I speak unto you with sharpness and with power, for mine arm is over all the earth.

3 And I will tell you that which no man knoweth save me and thee alone—

4 For many times you have desired of me to know that which would be of the most worth unto you.

5 Behold, blessed are you for this thing, and for speaking my words which I have given you according to my commandments.

6 And now, behold, I say unto you, that the thing which will be of the most worth unto you will be to declare repentance unto this people, that you may bring souls unto me, that you may rest with them in the kingdom of my Father. Amen." (Doctrine and Covenants 15)

"Revelation given through Joseph Smith the Prophet to Peter Whitmer Jr., at Fayette, New York, June 1829 (see the heading to section 14). Peter Whitmer Jr. later became one of the Eight Witnesses to the Book of Mormon.

1–2, The Lord’s arm is over all the earth; 3–6, To preach the gospel and save souls is the thing of most worth.

1 Hearken, my servant Peter, and listen to the words of Jesus Christ, your Lord and your Redeemer.

2 For behold, I speak unto you with sharpness and with power, for mine arm is over all the earth.

3 And I will tell you that which no man knoweth save me and thee alone—

4 For many times you have desired of me to know that which would be of the most worth unto you.

5 Behold, blessed are you for this thing, and for speaking my words which I have given unto you according to my commandments.

6 And now, behold, I say unto you, that the thing which will be of the most worth unto you will be to declare repentance unto this people, that you may bring souls unto me, that you may rest with them in the kingdom of my Father. Amen." (Doctrine and Covenants 16)

And here's the commentary entitled: "Bringing souls unto Christ is of great worth." : 

"Have you ever wondered, as John and Peter Whitmer did, what “would be of the most worth” in your life? (Doctrine and Covenants 15:4; 16:4). As you read Doctrine and Covenants 15–16, ponder why bringing souls to Christ is of such great worth. What are you doing to “bring souls” unto Christ?

See also Saints, 1:68–71."

Bringing souls unto Christ is indeed of great worth because we are helping our brothers and sisters and give them the opportunity to eventually qualify to receive eternal life as we do so. We are eternal beings as children of God. We lived with God as spirits before coming down here on earth. Our spirits united with our physical bodies when we were born here and we became souls with the opportunity to become more like God. When we die, our spirits and physical bodies will separate and will be reunited again during the resurrection. So, after this earthly existence is over, we're bringing our souls with us along with our experiences, knowledge, wisdom, and relationships that we formed. If we are able to help in bringing souls unto Christ while we are here on earth, how great will be our joy with them in the kingdom of our Father.