Back in the Philippines while visiting my in -laws ,
I saw an interesting practice. Upon leaving home,
the whole family, from the youngest to the oldest,
made the sign of the cross reverently.
I now make the sign of the cross before taking my meals,
and also when I leave home for work.
This practice of making the sign of the cross is the grace of Jesus cross and not magic formula. A reminder of how Jesus save us by dying on the cross for us.
"Let us, therefore, not be ashamed of the Cross of Christ; but though another hide it, do thou openly seal it upon thy forehead, that the devils may behold the royal sign and flee trembling far away.Make then this sign at eating and drinking, at sitting, at lying down, at rising up, at speaking, at walking: in a word, at every act." St Cyril Bishop of Jerusalem A.D. 386*
"Mark all your actions with the sign of the life giving Cross. Do not go out from the door of your house till you have signed yourself with the Cross. Do not neglect that sign whether in eating or drinking or going to sleep, or in the home or going on a journey. There is no habit to be compared with it. Let it be a protecting wall round all your conduct, and teach it to your children that they may earnestly learn the custom". St Ephrem of Syria.*
Our battle is against the kingdom of darkness. The evil spirits and fallen angel's kingdom is like a raging sea surrounding us from all sides, threatening our salvation. Over the centuries, the experience of the Church confirms that the demon are not able to withstand the representation of the Cross and the sign of the cross.
*extract taken from The sign of Cross-fish eaters http://www.fisheaters.com/sign.html