The picture above is of a miniature Christmas light. Christmas is the celebration of the first coming of Christ when God Almighty became incarnate, was born of a virgin, and lived as a baby in Bethlehem.
Advent is the season of holy days before Christmas, in other words the holidays before Christmas. It is the time when Christians prepare for the coming of Christ. Preparations commonly include repentance and times of quiet reflection and prayer.
Many people also put up lights during Advent in preparation for the coming of Christ. May God bless your Advent preparations, and fill your heart with light and truth.
Rejoice, rejoice, believers,
And let your lights appear;
The evening is advancing,
And darker night is near.
The Bridegroom is arising
And soon is drawing nigh.
Up, pray and watch and wrestle;
At midnight comes the cry.
— “Rejoice, Rejoice, Believers,” Lutheran Service Book, 515:1.