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The Gospel of Luke begins its account of Mary's life with the Annunciation, when the angel Gabriel appeared to her and announced her divine selection to be the mother of Jesus. According to gospel accounts, Mary was present at the Crucifixion of Jesus and is depicted as a member of the early Christian community in Jerusalem. According to Apocryphal writings, at some time soon after her death, her incorrupt body was assumed directly into Heaven, to be reunited with her soul, and the apostles thereupon found the tomb empty; this is known in Christian teaching as the Assumption.

What did Gabriel announce to Mary at the Annunciation?
her divine selection to be the mother of Jesus