If ye have desires to serve God, ye are called to the work

We are all called - continuously to serve God, discretely to other calls and modes of service. In the allegory of the olive tree, the Lord of the vineyard tells his servant to go and call other servants. We, as those called, may respond in one of three ways (there are other nuances, I am sure, but these are the three main ways I can think of):

1) We may be unprepared and hence afraid of the call. Adam, in the garden of Eden, when called by God, was ashamed and afraid because he was unprepared to meet God (Gen 3:10 or Moses 4:16). Alma the Younger, similarly, thinking of when he would be called into God's presence cried out and wished that he might be made extinct, both body and soul (Alma 36:15; see also Mosiah 2:36-39).

2) We may be unprepared, but filled with pride. When Father asked whom He could send, Lucifer volunteered for the position (Moses 4:1, Abraham 3:27-28). Christ had be selected and prepared from the beginning to be the Savior. Lucifer had not received that same training. He was unprepared to fulfill the role as it needed to be. yet, in his pride, he thought he could best God and propose a new plan, with him at its center. President Benson in "Beware of Pride" indicated that it was Satan's prideful desire to dethrone God (see also DC 76:28). His pride blinded him to his lack of preparation, and rather than submit to God's will, he chose to rebel. You could argue that this group is not truly called, yet, but calls themselves and takes the honor unto themselves (Hebrews 5:4).

3) We may be prepared and willing. This is the response of Israel/Jacob (Genesis 46:2, 31:11), Isaac (Genesis 22:7), Abraham (Genesis 22:11), Moses (Exodus 3:4), Samuel (1 Samuel 3:10), Isaiah (Isaiah 6:8), and Christ (Abraham 3:27). And hopefully each of us. Note that Isaiah and Moses (we could add Enoch and several others) expressed their concern about their lack of preparation; the Lord made up the difference. I am sure some of the others may have felt similarly. Isaac asked to be bound that he might not interfere with what he knew to be the Lord's will.

What is the preparation of each of these servants of God and Christ? What preparation is needed of each of us as we are called?
Psalms 24:3-4 indicates we need 4 things to worthily be in God's presence and DC 121:45 adds 1.5 more.

1) clean hands - Isaiah 1:16-19 and Alma 13:11 combine to make it clear that our hands, garments, and sins are to be washed clean in the blood of the Lamb. We are to avail ourselves of the atonement at every opportunity.

2) pure heart (including virtue garnishing thoughts unceasingly) - A pure heart means that you are not dividing your attentions (Matthew 6:24), but that you have an eye single to the glory of God (DC82:19, see also Moses 1:39 for what our eye's should be single to); the Lord requires the heart and a willing mind (DC64:34).

3) no vanity - we must press forward, relying wholly on the merits of Him who is mighty to save (2 Nephi 31:19) so that we acknowledge His hand in all things and lean not unto our own understanding (Proverbs 3:5-6) and this, along with Charity, will help to preserve us from pride that there be no vanity in us.

4) no deceit - God will not be mocked (Galatians 6:7, DC124:71, see also Zeezrom in Alma 11-12 and Sherem in Jacob 7). We also learn in DC 121 that the priesthood and the Spirit both are withdrawn from those who attempt to exercise vanity in their calling.

5) Charity - Charity is a gift of God, through the Spirit. You cannot properly serve anyone for whom you have not developed at least a little charity. The greater your charity toward someone the easier and more joyous and more rewarding your service will be. You will also not begrudge the time spent in the service. This is more from my own experience than from a reading of the scriptures, but that does not make it less true.

Psalms 24 indicates that these attributes qualify us to ascend into the hill of the Lord and stand in His holy place, that is, to go where He is and stand with Him. DC 121:45 adds that our confidence shall wax strong in God's presence, that is, we will be comfortable in His presence, which to me means that we will be worthy and invited to be there. Ultimately, what these and other scriptures indicate is that these attributes, along with the others that you develop while in the service of God (or your fellow men Matthew 25:40, Mosiah 2:17) qualify you for Eternal Life with God. Therefore, each call to serve is a call to exaltation: the Lord calling you from the wilderness into His home.

P.P. (post post :), as opposed to post script)

I wish to note that there is no such thing as prepared and unwilling. Your unwillingness to serve disqualifies you for the divine help, without which you cannot succeed. Elder Bednar taught that the Lord does not call a man because of who he is or what he has done, but because of who he may become, through the service.

Similarly, there is no such thing as unprepared and willing. Your willingness qualifies you for the help of the Spirit, which is the quintessential element in any preparation (see also DC 4:5 - faith, hope, charity (which are gifts of the Spirit) and an eye single to the glory of God (which is your willingness to serve in the Lord's way) qualify (=prepared) you for the work). What you may lack at the outset you will gain along the way, if you permit God to lead you.