Mark 3:13-21, Luke 6:12-16

Luke tells the that the Savior -

"...went out into a mountain to pray, and continued all night in prayer to God.
13 ¶ And when it was day, he called unto him his disciples: and of them he chose twelve, whom also he named apostles;
14 Simon, (whom he also named Peter,) and Andrew his brother, James and John, Philip and Bartholomew,
15 Matthew and Thomas, James the son of Alphæus, and Simon called Zelotes,
16 And Judas the brother of James, and Judas Iscariot, which also was the traitor." (New Testament Luke 6:12 - 16)

As we ponder that Savior prayed all night and then called called twelve from all His disciples, you would have to assume the Savior was in sincere prayer to learn the will of God in the choosing of them that he would call apostles. In other words, these twelve were literally called of God. It becomes apparent that his apostles were seperate from his disciples. Mark tells us -

"...he ordained twelve, that they should be with him, and that he might send them forth to preach,
15 And to have power to heal sicknesses, and to cast out devils..." (New Testament Mark 3:14 - 15)

As apostles, the Savior later teaches them -

"...Ye have not chosen me, but I have chosen you, and ordained you, that ye should go and bring forth fruit, and that your fruit should remain: that whatsoever ye shall ask of the Father in my name, he may give it you." (New Testament John 15:16)

These men were specifically chosen, and not only chosen, but ordained. Paul taught of priesthood ordinations and callings -

"...no man taketh this honour unto himself, but he that is called of God..." (New Testament Hebrews 5:4)

Joseph Smith later taught -

"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." (Pearl of Great Price Articles of Faith 1:5)

Paul taught there are many offices or callings in the priesthood for the Savior -

"...gave some, apostles; and some, prophets; and some, evangelists; and some, pastors and teachers;
12 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..." (New Testament Ephesians 4:11 - 13)

Elder Talmage taught of the specific ordination and calling of an apostle -

“Discipleship is general; any follower of a man or devotee to a principle may be called a disciple. The Holy Apostleship is an office and calling belonging to the Higher or Melchizedek Priesthood, at once exalted and specific, comprising as a distinguishing function that of personal and special witness to the divinity of Jesus Christ as the one and only Redeemer and Savior of mankind. The apostleship is an individual bestowal, and as such is conferred only through ordination.” (Talmage, Jesus the Christ, p. 227. Italics added.)

As Peter moved to fill the vacancy of the Quorum of Twelve caused by the apostasy of Judas, he instructed the disciples of the requirements of an apostle -

"Wherefore of these men which have companied with us all the time that the Lord Jesus went in and out among us,
22 Beginning from the baptism of John, unto that same day that he was taken up from us, must one be ordained to be a witness with us of his resurrection..." (New Testament Acts 1:21 - 22)

President Harold B. Lee teachs of important principle as he relates -

“May I impose to bear my own testimony. I was visiting with one of the missionaries some years ago when two missionaries came to me with what seemed to be a very difficult question, to them. A young Methodist minister had laughed at them when they had said that apostles were necessary today in order for the true church to be upon the earth. And they said the minister said: ‘Do you realize that when they met to choose one to fill the vacancy caused by the death of Judas, that they said it had to be one who companied with them and had been a witness of all things pertaining to the mission and resurrection of the Lord? How can you say you have apostles, if that be the measure of an apostle?’ And so these young men said, ‘What shall we answer?’ I said to them: ‘Go back and ask your minister friend two questions. First, how did the Apostle Paul gain what was necessary to be called an apostle? He didn’t know the Lord; had no personal acquaintance. He hadn’t accompanied the apostles. He hadn’t been a witness of the ministry, nor the resurrection of the Lord. How did he gain his testimony sufficient to be an apostle? Now the second question you ask him: How does he know that all who are today apostles have not likewise received that witness?’ I bear witness to you that those who hold the apostolic calling may, and do know of the reality of the mission of the Lord.” (“Born of the Spirit,” Address to Seminary and Institute Faculty, 26 June 1962.)

It is a apparent that each office and calling in the priesthood brings with with it a solemn oath of being -

"...faithful unto the obtaining these two priesthoods...and the magnifying their calling..." (Doctrine and Covenants Section 84:33)

Returning to the example the Savior praying all night in prayer to know and the will of God, we too should do the same in our offices and callings. Paul explains the simpleness of the way with Jesus Christ -

"..For we have not an high priest which cannot be touched with the feeling of our infirmities; but was in all points tempted like as we are, yet without sin.
16 Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need." (New Testament Hebrews 4:15 - 16)