Signs and Symbols

Someone once asked me, why do Catholics genuflect or make the sign of the cross?
Taken from here.

Genuflecting:
Catholics believe Jesus is truly present in the Tabernacle. If I ask an Evangelical what he would do if he saw Jesus standing in front of him he would say "I would fall to my knees." Although a Bible Christian may disagree on the real presence of Jesus, he will certainly not disagree that bending to one's knees is an appropriate response to the real presence of Jesus. One Evangelical told Father Bob Bedard, "If I believed what you believed, that Jesus is really present in the Eucharist, I'd be at Church every day and I would fall to my knees when I entered." Ditto, I go to Church every day and fall to my knees when I enter.

Sign of the Cross:
Evangelicals see this as a way of spotting a Catholic from a mile away. But this is a very old practice. Christians have been doing it from early times. The theologian Tertullian recorded it in 211 A.D. I got an email that said:

"I was wondering what it means when before the gospel we make a sign small sign of the cross on our forehead, lips, and heart." (original spelling)

Mark Bonomero responds that it is a silent prayer --a response to the announcement of the Gospel reading where the priest or deacon says: "A reading from the holy Gospel according to John." And the congregation, tracing the cross over their forehead, lips, and heart, is supposed to say to themselves (silently); "May the Words of the Gospel be on my mind, upon my lips, and in my heart." At the same time, of course, we vocally respond: "Gloria tibi Domine" ("Glory to you, oh Lord.").

Tracing the little cross over our forehead is actually the original form of the Sign of the Cross -the one used by the earliest Christians, before the Council of Nicea. What it is, is tracing where the bishop placed the oil (in the form of a cross) on your forehead at Confirmation. The present Sign of the Cross was developed around the time of Nicaea itself so as to deny the error of Arianism and express belief in the Trinity as the Council of Nicaea defined it.

More reading on signing of the cross.