"You have been indebted to other men, in the first instance, for evidence; on that you have acted; but it is necessary that you receive a testimony from heaven for yourselves; so that you can bear testimony to the truth of the Book of Mormon, and that you have seen the face of God. That is more than the testimony of an angel. When the proper time arrives, you shall be able to bear this testimony to the world. When you bear testimony that you have seen God, this testimony God will never suffer to fall, but will bear you out; although many will not give heed, yet others will. You will therefore see the necessity of getting this testimony from heaven.
"Never cease striving until you have seen God face to face. Strengthen your faith; cast off you doubts, your sins, and all your unbelief; and nothing can prevent you from coming to God. Your ordination is not full and complete till God has laid His hand upon you. We require as much to qualify us as did those who have gone before us; God is the same. If the Savior in former days laid His hands upon His disciples, why not in latter days?" (Oliver Cowdery, HC v 2, ch 13, p 195)
The Father and Son appear in the School of the Prophets
The salutation as written in the Doctrine and Covenants [D&C 88:136-141] was carried out at that time, and at every meeting, and the washing of feet was attended to, the sacrament was also administered at times when Joseph appointed, after the ancient order; that is, warm bread to break easy was provided and broken into pieces as large as my fist and each person had a glass of wine and sat and ate the bread and drank the wine; and Joseph said that was the way that Jesus and his disciples partook of the bread and wine. And this was the order of the church anciently and until the church went into darkness. Every time we were called together to attend to any business, we came together in the morning about sunrise, fasting and partook of the sacrament each time, and before going to school we washed ourselves and put on clean linen.
At one of these meetings after the organization of the school, (the school being organized_ on the 23rd of January, 1833, when we were all together, Joseph having given instructions, and while engaged in silent prayer, kneeling, with our hands uplifted each one praying in silence, no one whispered above his breath, a personage walked through the room from east to west, and Joseph asked if we saw him. I saw him and suppose the others did and Joseph answered that is Jesus, the Son of God, our elder brother. Afterward Joseph told us to resume our former position in prayer, which we did. Another person came through; he was surrounded as with a flame of fire. He (Brother Coltrin) experienced a sensation that it might destroy the tabernacle as it was of consuming fire of great brightness. The Prophet Joseph said this was the Father of our Lord Jesus Christ. I saw Him.
When asked about the kind of clothing the Father had on, Brother Coltrin said: I did not discover his clothing for he was surrounded as with a flame of fire, which was so brilliant that I could not discover anything else but his person. I saw his hands, his legs, his feet, his eyes, nose, mouth, head and body in the shape and form of a perfect man. He sat in a chair as a man would sit in a chair, but this appearance was so grand and overwhelming that it seemed I should melt down in his presence, and the sensation was so powerful that it thrilled through my whole system and I felt it in the marrow of my bones. The Prophet Joseph said: Brethren, now you are prepared to be the apostles of Jesus Christ, for you have seen both the Father and the Son and know that they exist and that they are two separate personages.
This appearance occurred about two or three weeks after the opening of the school. After the Father had passed through, Joseph told us to again take our positions in prayer. We did so, and in a very short time he drew our attention and said to us that Brother Reynolds Cahoon was about to leave us, and told us to look at him. He (Brother Cahoon) was on his knees and his arms were extended, his hands and wrists, head, face and neck down to his shoulders were as a piece of amber, clear and transparent, his blood having apparently left his veins. Upon the attention of the brethren being thus called to Brother Cahoon, the change seemed to pass away and Joseph said that in a few minutes more, Brother Cahoon would have left us, but he came to himself again." ("Statement of Zebedee Coltrin," Minutes, 3 October 1883, Salt Lake School of Prophets, LDS Church Archives, Salt Lake City, Utah, 56-58; see also Lyndon W. Cook, The Revelations of the Prophet Joseph Smith (Salt Lake City, Utah: Deseret Book, 1981, See also Joseph Smith Papers, Documents, Volume 3, p. 43), 187-88)
"...[the glory of the Father] was so great that had it continued much longer, I believe it would have consumed us." ("Zebedee Coltrin Address, Minutes of the High Priest Meeting, Spanish Fork, Utah, February 5, 1878," LDS Church Archives, Salt Lake City, Utah, 103)
Calling and requirement of Apostles in New Testament:
And in those days Peter stood up in the midst of the disciples, and said, (the number of names together were about an hundred and twenty,) Men and brethren, this scripture must needs have been fulfilled, which the Holy Ghost by the mouth of David spake before concerning Judas, which was guide to them that took Jesus. For he was numbered with us, and had obtained part of this ministry. Now this man purchased a field with the reward of iniquity; and falling headlong, he burst asunder in the midst, and all his bowels gushed out. And it was known unto all the dwellers at Jerusalem; insomuch as that field is called in their proper tongue, Aceldama, that is to say, The field of blood. For it is written in the book of Psalms, Let his habitation be desolate, and let no man dwell therein: and his bishoprick let another take. Wherefore of these men which have companied with us all the time that the Lord Jesus went in and out among us, 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.
And they appointed two, Joseph called Barsabas, who was surnamed Justus, and Matthias. And they prayed, and said, Thou, Lord, which knowest the hearts of all men, shew whether of these two thou hast chosen, That he may take part of this ministry and apostleship, from which Judas by transgression fell, that he might go to his own place. And they gave forth their lots; and the lot fell upon Matthias; and he was numbered with the eleven apostles. (Acts 1:15-26)