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. Then Joseph her husband, being a just man, and not willing to make her a public example, was minded to put her away privily. 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. And she shall bring forth a son, and thou shalt call his name JESUS: for he shall save his people from their sins. . . . Then Joseph being raised from sleep did as the angel of the Lord had bidden him, and took unto him his wife. 

To Christians, Jesus’ birth to a virgin was foretold in Isaiah 7:14—“The Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel” (see Matthew 1:22, 23)—and fulfilled at this time. (Some translators use the term young woman instead of virgin.) The oracle is associated with Christ Jesus’ arrival to this day.

Since unfaithfulness to a betrothal was deemed adultery, Joseph—portrayed as just (Greek, dikaios, signifying faithful to the law)—would have had the right to shame Mary publicly by bringing her before a court. His decision to end the engagement privately (to “put her away privily”) is a kind and generous resolution that honors the law while respecting Mary. Joseph’s righteous character is again illustrated by his obedience to the divine command to take Mary as his wife.