The mass begins with a procession in which the celebrant goes to the sanctuary. Most commonly, it is the celebrant and ministers that approach the sanctuary in procession. However, we also walk spiritually with them. That is the meaning of the procession, to symbolize that Christians are a people that walks as pilgrims in life. If we fall, to get up, to continue our walk towards the Holy City. The procession is not a parade of those who will participate in the mass, so that we can see them closely. It is an allegory of the Christian walk towards God1.
When they have arrived at the sanctuary, the Priest, the Deacon, and the ministers reverence the altar with a profound bow. Moreover, as an expression of veneration, the Priest and Deacon then kiss the altar itself; the Priest, if appropriate, also incenses the cross and the altar. (General Instruction of the Roman Missal 49)
When the Entrance Chant is concluded, the Priest stands at the chair and, together with the whole gathering, signs himself with the Sign of the Cross. Then by means of the Greeting he signifies the presence of the Lord to the assembled community. By this greeting and the people’s response, the mystery of the Church gathered together is made manifest. (GIRM 50)
1 Liturgia Papal, “Vivir la Misa”, LiturgiaPapal.org, https://liturgiapapal.org/attachments/article/960/Iniciales1.pdf, accessed 20 september 2022