Why do some people bend down on one knee before entering or exiting the pew? And…oh, yeah: Why do some folk make the crossing motion during the Mass?
In both these actions, the purpose is to show worshipful honor to Our Lord Jesus Christ. In the bronze tabernacle behind the Altar, the Reserved Sacrament of Christ’s Body is kept. So, when we are in the Church, we are in the very Presence of the Jesus Christ in the Blessed Sacrament. Therefore, we bend the knee to our King each time we enter and exit our pew. We are adoring Him and giving Him, the honor which is due the Son of God. The “Sign of the Cross” is made when Christ’s Cross and Passion are said out loud, and when we invoke the Trinity, “Blessed be God, the Father, the Son, and the Holy Spirit”. Once again, the “Why” is because we are baptized into the Divine Name, and we offer the Sign of the Cross in awe-filled wonder at His saving Death & Resurrection for us. (Fr. Smith)