Catholics have made the sign of the Cross since earliest times. Terrullian, who died about 240 AD and St Ephrem who died in 373 both speak about Christians making the sign of the cross. It is the first sign made on us when we are baptised and the last when we die.
The Sign of the Cross expresses blessing. It symbolizes God blessing us, God embracing us with blessings. And in this same sign we express our belief in God from whom all our blessings flow. In the Sign of the Cross we embrace our good God with mind and heart and all of our strength.
When we bless ourselves with the Sign of the Cross we remember the One who blesses us: the triune God, Father, Son and Holy Spirit.
Blessed by the Cross
With the Sign of the Cross we recall in particular the blessing of the life, death and resurrection of Jesus Christ. We trace a cross on ourselves, the cross of Jesus. His death on the Cross was an outpouring of love for us. The Sign of the Cross is a reminder of his love, a love found not only in the past, but here and now, as we make this sign upon ourselves; for the love of Jesus Christ abides forever.
The Sign of the Cross is a wonderful daily expression of our relationship with God. God is the One who blesses. This prayer reminds us that each day, in good times and bad, in danger and sorrow, God's care and blessings are never far from us.
Tracing this holy sign on our forehead, our hearts and our shoulders, we remember we are blessed in mind and heart and all our being.
References : http://www.cptryon.org/prayer/sign.html
Victor Hoagland CP
Radio Replies Volume I No. 1343