“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.”
King James Version (KJV)
Mt 1:20 While he thought. Reflected, still in doubt, perplexed. The angel. Gabriel appeared to Mary (Lu 1:26); the name of the angel is not here given. Angels are messengers; an angel of the Lord is the Lord's messenger. These messengers are usually superhuman, but not always. In a dream. Often messages were conveyed by impressions made in sleep. Three times revelations were thus made to Joseph. Thou son of David. It was fitting that he should now be reminded that he belonged to the family from whence the Messiah was to come. Fear not. His betrothed was pure.