Matthew 1:24

20But when he thought about these things, behold, an angel of the Lord appeared to him in a dream, saying, “Joseph, son of David, don’t be afraid to take to yourself Mary as your wife, for that which is conceived in her is of the Holy Spirit.

21She shall give birth to a son. You shall name him Jesus, for it is he who shall save his people from their sins.”

22Now all this has happened that it might be fulfilled which was spoken by the Lord through the prophet, saying,

23“Behold, the virgin shall be with child, and shall give birth to a son. They shall call his name Immanuel,” which is, being interpreted, “God with us.”

24Joseph arose from his sleep, and did as the angel of the Lord commanded him, and took his wife to himself;

25and didn’t know her sexually until she had given birth to her firstborn son. He named him Jesus.