This feast is also called the "Presentation of Christ in the Temple" and "Candlemas."
In accordance with Jewish law and forty days after the birth of Jesus, Mary went to the Temple of Jerusalem for her purification, the story of which is told in Luke 2:22-32.
While there, the aged Simeon took Jesus into his arms, and uttered what we now call the Nunc Dimittis - "Lord now lettest thou thy servant depart in peace..."
The blessing of candles, which also occurs this day, recalls Simeon's declaration regarding Jesus, who is the "light to lighten the Gentiles, and... the glory of thy people Israel."
As the day's offertory puts it, as Jesus "was this day presented in the temple in the substance of flesh," may we also "be presented unto God with pure and clean hearts."(The day's offertory, page E 26, People's Anglican Missal)