March 25 is the Great Feast of the Annunciation. March 26 is the Synaxis of the Archangel Gabriel.
"Hearken, O Maiden, virgin and pure, that Gabriel may tell the eternal will of the Highest. Make thee ready to receive God; for the Uncontainable shall, through thee, mingle with mankind."
Visit the Department of Sacred Music  for liturgical musical resources for the Feast.
The Boy Who Died and the Boy Who Lived: On the Annunciation , by Douglas Cramer
The Annunciation of the Virgin Mary , by Metropolitan Hierotheos (Vlachos)