Pope Shenouda III
When we make the sign of the  cross, we profess that we belong to the Crucified
  Those who take  the cross only by its  spiritual meaning inside the heart without  showing any manifest sign do  not reveal this belonging openly which we  proclaim in making the sign of  the cross, in wearing and kissing the  cross in front of all, in  engraving it on our wrists and in upraising  it on our places of worship,.  By  doing all these we are merely proclaiming our belief openly. We are   not ashamed of Christ's cross in front of people but we glory in it, are   called by it, celebrate its feasts and cling tort so that, even  without  us talking, our appearance professes our belief.