Essentially, the idea is that it is the Lord that has called, or asked, a person to perform a specific duty in the Church. This doctrine can be found in the fifth LDS Article of Faith,
- We believe that a man must be called of God, by prophecy, and by the laying on of hands by those who are in authority, to preach the Gospel and administer in the ordinances thereof.
For a calling to be seen as legitimate, it must be given by a person that has the authority to give it. For example if a calling is at the ward level such as a teacher, the ward leader, the bishop, calls that person. However, if the calling is on a stake level, someone who has authority over the stake, such as a stake president, must give the calling.
Receiving a calling is not like getting a promotion at work. There is no calling that is above another, they are all needed and are an important part of Christ’s Church. Some callings, however, do come with more responsibility. For example, a bishop is responsible for the welfare of his entire ward (or congregation), while a Relief Society President is responsible for only the women in the ward. However, both of the positions are equally important because they help to further Christ’s kingdom. Romans 12:3-5 offers an example of this idea,
- For I say, through the grace given unto me, to every man that is among you, not to think of himself more highly than he ought to think; but to think soberly, according as God hath dealt to every man the measure of faith. For as we have many members in one body, and all members have not the same office: So we, being many, are one body in Christ, and every one members one of another.
Thus any calling that helps edify members and strengthen Christ's Church is important.
After a person has been called, their name will be presented for a sustaining vote during Sacrament meeting (if it the calling is at a ward level). A member of the bishopric reads the name of the person called, tells what they have been called to, and asks the congregation for a sustaining vote. Sustaining entails the members of the congregation raising their right arms to the square. By so doing the members indicate that they believe the calling has come from the Lord and that they are willing to support that person in their new calling. If for some reason a ward member feels they cannot sustain a person, they are invited to discuss their concerns with the Bishop after the meeting.
Once the person called has been sustained by the congregation they will then meet with the bishopric, to be "set apart." Being set apart involves receiving a priesthood blessing by the laying on of hands. The person is blessed with all the keys and authority they will need to fulfill their calling.
When the Lord sees fit, or as circumstances dictate the need, a person will be released from their calling. Typically, the person will be given a new calling and a new person will receive their previous calling. During Sacrament meeting, a member of the bishopric will announce that a person has been released and ask the congregation for a vote of thanks (which, like sustaining, involves raising the right arm to the square).
Some of the callings in a ward include: Bishopric (bishop and two counselors), Elder’s quorum presidency (all presidencies include a president and two counselors), Relief Society Presidency, Young Women’s Presidency, Primary Presidency, Young Men’s Presidency, Sunday School Presidency, High Priest Group Leader, Visiting Teacher, Home Teacher, Ward Clerk, Activities Board, Teachers, Ward Librarian, Ward Organist, and many others.