I'm sure as Joseph Smith sat in Carthage Jail this verse took on significant meaning for him:
In pris'n I saw him next, condemned
To meet a traitor's doom at morn.
The tide of lying tonuges I stemmed,
And honored him 'mid shame and scorn.
My friendship's utmost zeal to try,
He asked if I for him would die.
The flesh was weak, my blood ran chill,
But my free spirit cried, "I will"
I'm grateful Christ has not yet required my life. He has asked me to do other things though. One of which is give up 2 years to serve a mission. Along with that comes many other responsibilities. I am asked to talk to everyone, to invite others to be baptized, to follow a missionary schedule, to build up the ward where I serve, and the list of things goes on. These things seem so little to me when compared to what others have done for Christ. It matters not what he asks us to do. What matters is whether or not we are willing to do it.
The reason why Joseph Smith, myself, and many others act when they are called is simply because Jesus is the Christ. We understand that Christ has given us his all. He gave us his life. He suffered for our sins, sorrows, pains, temptations, and afflictions. He was despised and rejected of men. He descended below all things. Yet he overcame death. He conquered sin. He rose above all things. He sits at the right hand of the Father. All power is given to him in heaven and in earth. He is our Savior and our Redeemer.
If he did all those things for me I know that I can do all things through him. In fact he has promised me all things if I am faithful. These promises are extended to as many as will come unto him. His arms are open to everyone. He invites everyone to "Repent and come unto me and bebbaptized in my name, that ye may be sanctified by the reception of the Holy Ghost, that ye may stand spotless before me at the last day."(3 Nephi 27:20)
This is my calling: to invite others to come unto Christ by helping them to recieve the restored Gospel through faith in Jesus Christ and his Atonement, repentance, baptism, recieving the gift of the Holy Ghost, and enduring to the end. I am here to open the doors of the Celestial Kingdom to the sons and daughters of God. I do these things because Jesus is the Christ.
Find out how you can serve Christ by reading the rest of the lyrics to "A Poor Wayfaring Man of Grief"
Read in the Book of Mormon what Christs expects of you, "2 Nephi 9)