Matthew 1:19-23

And Joseph her [promised] husband, being a just and righteous man and not wanting to expose her publicly to shame, planned to send her away and divorce her quietly. But after he had considered this, an angel of the Lord appeared to him in a dream, saying, “Joseph, descendant of David, do not be afraid to take Mary as your wife, for the Child who has been conceived in her is of the Holy Spirit. She will give birth to a Son, and you shall name Him Jesus (The LORD is salvation), for He will save His people from their sins.” All this happened in order to fulfill what the Lord had spoken through the prophet [Isaiah]: “BEHOLD, THE VIRGIN SHALL BE WITH CHILD AND GIVE BIRTH TO A SON, AND THEY SHALL CALL HIS NAME IMMANUEL”—which, when translated, means, “GOD WITH US.” [Is 7:14]