Advent, the coming of Christ. Here's a prayer, from the 1928 BCP, obvs:
Almighty God, give us grace that we may cast away the
works of darkness, and put upon us the armor of light, now
in the time of this mortal life in which thy Son Jesus Christ
came to visit us in great humility; that in the last day, when
he shall come again in his glorious majesty to judge both the
quick and the dead, we may rise to the life immortal; through
him who liveth and reigneth with thee and the Holy Ghost,
one God, now and for ever. Amen.
LSP