On any occasion, let us trace te Sign of the Cross with our fingers: when we eat bread or drink, when we enter or exit, before going to sleep, when we are lying down or when we rise, whether we are moving or sitting still. It is an efficacious aid that is free for the poor and effortless for the weak. In fact, it is a grace from God: the mark of believers and the terror demons.
Cyril of Jerusalem
Catechetical Lectures, XIII, 35-36
Lent and Easter with the Early Church Fathers