Russian Orthodox Church Protection of Mother of God
Russian Orthodox Church • Patriarchial Parishes in Canada

According to the Law of Moses, all Hebrew parents must bring their first born son on the fortieth day after birth to the Temple to be consecrated to God. It was the custom to bring a sacrifice in thanksgiving to God. The law was established in remembrance of the exodus of the Hebrews from Egypt — freedom from slavery — when the first-born Hebrews were spared from death. In fulfilment of this law, the Mother of God with Joseph brought the infant Jesus to the Temple in Jerusalem and brought for the sacrifice two fledgling doves.  Simeon and Anna, the prophets of Israel, being instructed by the Holy Spirit, met Him as the promised Christ the Saviour. And Saint Simeon the God­Receiver foretold to the Mother of God: Behold, this child is set for the fall and rising again of many in Israel; and for a sign which shall be spoken against; (yea, a sword shall pierce through thy own soul also,) that the thoughts of many hearts may be revealed (Luke 2:34­35). 

This event, in which Saints Simeon and Anna met in the Temple the infant Christ presented by the Mother of God and Joseph and glorified Him, is called the Feast of the Meeting of the Lord and is celebrated in the Holy Orthodox Church as one of the great feast days. 

Troparion of the Feast

Rejoice, Thou Who art full of grace, O Virgin Theotokos, for from Thee hath risen the Sun of Righteousness, Christ our God, enlightening those in darkness. Rejoice, thou also, O righteous Elder, as thou receivest in thine arms the Redeemer of our souls, Who also granteth unto us the Resurrection.

Based on the articles posted at Orthodox Christianity.