above image taken from: https://reflectionary.org/2021/01/01/chalking-the-doorway-a-house-blessing-for-epiphany/
There is a tradition of blessing chalk at Epiphany to mark the threshold of our homes with a new year blessing. It’s been common in parts of Europe – especially Catholic countries – for a long time and has spread to the UK and the US in recent years.
It picks up Jewish traditions of marking the doorposts of the house with biblical texts:
Hear, O Israel: The Lord our God, the Lord is one. Love the Lord your God with all your heart and with all your soul and with all your strength. These commandments that I give you today are to be on your hearts. Impress them on your children. Talk about them when you sit at home and when you walk along the road, when you lie down and when you get up. Tie them as symbols on your hands and bind them on your foreheads. Write them on the doorframes of your houses and on your gates. (Deuteronomy 6:4-9)
It can also remind us of the Holy Family welcoming visitors to their home to visit the Christ-child and is a reminder of the importance of hospitality throughout the Scriptures. Because of the timing of Epiphany, it offers a chance to pray for God’s blessing at the start of the new year.
The letters and numbers that people chalk on their doors pick up the new year, the Epiphany story, and the prayer for blessing in a simple formula, written like this 20 + C + M + B + 25. The 20 and 25 are of course the beginning and end of the year’s date. The middle three letters stand for the traditional names of the wise men (magi): Caspar, Melchior and Balthasar. They also represent the initials of the Latin phrase “Christus mansionem benedicat” – “Christ bless the house.” Together they represent our prayer at the start of the year that our homes and places of worship may be places blessed by the love and light of Christ.
On Tuesday 7th January we will be blessing some chalk at the Centre at our Reflective Communion and offering it to people who might wish to chalk their own doors. We will also be chalking the door of the Centre. If you wish to chalk your door you might like to use this prayer as you do so:
Visit, Lord, we pray, this home with the joy of your presence.
Bless all who live here with the gift of your love.
Help us share your care and compassion with one another,
to make this a place of welcome and strength,
of blessing and friendship,
that all who pass through this doorway
may find a hearth and home lit by the light of love.
May we grow with Christ in truth and wisdom,
as we learn to follow in his steps,
and take on his yoke,
that we may be blessed by his grace,
and find refreshment for ourselves, soul and body,
as we walk in his light into the adventure of this new year.
We make our prayer through the same Christ our Lord. Amen.
Some material from https://cofe-worcester.org.uk/news/epiphany-blessing-of-the-chalk.php