¶Now the birth of Jesus Christ was on this wise: When as his mother Mary was espoused to Joseph, before they came together, she was found with child of the Holy Ghost.
19 Then Joseph her husband, being a just man, and not willing to make her a publick example, was minded to put her away privily.
20 But while he thought on these things, behold, the angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Ghost.
21 And she shall bring forth a son, and thou shalt call his name JESUS: for he shall save his people from their sins.
22 Now all this was done, that it might be fulfilled which was spoken of the Lord by the prophet, saying,
23 Behold, a virgin shall be with child, and shall bring forth a son, and they shall call his name Emmanuel, which being interpreted is, God with us.
24 Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and took unto him his wife:
25 And knew her not till she had brought forth her firstborn son: and he called his name JESUS.
“When Mary told Joseph that she was with child by the power of the Holy Ghost, his reaction was one not only of shock, of sorrow, and of dismay, but also of disbelief. His soul had yet to feel the flames of the refiner’s fire before so great a spiritual truth could rest easily in his heart; as with all men, his faith and his willingness to submit to the divine will in all things must be tested.
“For Mary it was no easy thing to tell the man she loved that their relationship was different from that of other faithful couples. And yet Gabriel himself had brought the word! When she recited to Joseph what the aerial ambassador had told her, great and wondrous as the promises were, it must yet have been as a sword piercing her soul, a sword that would wound her feelings time and again, until that day when she, at the foot of a cross, would weep for the Son whom she had brought into the world.
“For Joseph it was the beginning of a period of agony and uncertainty. That he wanted to believe Mary, but did not, is shown by his determination ‘to put her away privily’ with as little embarrassment as possible.” (Bruce R McConkie, The Mortal Messiah: From Bethlehem to Calvary, 1:331-2.)