Ephesians 2 & 4

Paul tells those who had been baptized and were then members of the Church -

"...ye are no more strangers and foreigners, but fellowcitizens with the saints, and of the household of God..." (New Testament Ephesians 2:19)

The very covenant we make at baptism is what Alma stated as he said to his people -

"Behold, here are the waters of Mormon (for thus were they called) and now, as ye are desirous to come into the fold of God, and to be called his people, and are willing to bear one another's burdens, that they may be light;
9 Yea, and are willing to mourn with those that mourn; yea, and comfort those that stand in need of comfort, and to stand as witnesses of God at all times and in all things, and in all places that ye may be in, even until death, that ye may be redeemed of God, and be numbered with those of the first resurrection, that ye may have eternal life—
10 Now I say unto you, if this be the desire of your hearts, what have you against being baptized in the name of the Lord, as a witness before him that ye have entered into a covenant with him, that ye will serve him and keep his commandments, that he may pour out his Spirit more abundantly upon you?" (Book of Mormon Mosiah 18:8 - 10)

I like the quote given by Marion D. Hanks of what a young convert from England said -

"...You feel like you never are going to be lonely again,’ she wrote. And she shouldn’t ever be lonely again in this Church because she had become, as Paul wrote to the Ephesians, ‘fellowcitizens with the saints, and of the household of God." (Hanks, The Gift of Self, pp. 105–7.)

Paul explains that the household of God or His Church is -

"...built upon the foundation of the apostles and prophets, Jesus Christ himself being the chief corner stone..." (New Testament Ephesians 2:20)

In addition -

"...he gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers..." (New Testament Ephesians 4:11)

For the purpose -

"...the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ:
13 Till we all come in the unity of the faith, and of the knowledge of the Son of God, unto a perfect man, unto the measure of the stature of the fulness of Christ..." (New Testament Ephesians 4:12 - 13)

Is there any question what the mission and the Church and its priesthood leaders are? To help us to become more like Christ. Each of these priesthood leaders have different assignments. Some are to travel as the apostles and prophets which are -

"...a Traveling Presiding High Council, to officiate in the name of the Lord, under the direction of the Presidency of the Church, agreeable to the institution of heaven; to build up the church, and regulate all the affairs of the same in all nations..." (Doctrine and Covenants Section 107:33)

This would include the Seventy. There are those who pastors and teachers that -

"...are ordained to be standing ministers to my church..." (Doctrine and Covenants Section 124:137)

This would be those of the priesthood in local stakes. And there are evangelical ministers whom Joseph described as Patriarchs saying -

“there should be a patriarch for benefit of the posterity of the saints, as it was with Jacob in giving his patriarchal blessing unto his sons.” (Teachings, p. 151.)

Each priesthood holder doing their part -

"...speaking the truth in love, may grow up into him in all things, which is the head, even Christ:
16 From whom the whole body fitly joined together and compacted by that which every joint supplieth, according to the effectual working in the measure of every part, maketh increase of the body unto the edifying of itself in love." (New Testament Ephesians 4:15 - 16)

All priesthood offices given again for -

"For the perfecting of the saints, for the work of the ministry, for the edifying of the body of Christ:
13 Till we all come in the unity of the faith, and of the knowledge of the Son of God, unto a perfect man, unto the measure of the stature of the fulness of Christ:
14 That we henceforth be no more children, tossed to and fro, and carried about with every wind of doctrine, by the sleight of men, and cunning craftiness, whereby they lie in wait to deceive..." (New Testament Ephesians 4:12 - 14)