Beginning and Ending the Mass with a Kiss

Catholics kiss many things such as a crucifix on Good Friday, a medal, statue, image or relic of a saint, or a rosary after prayer.  Two kisses that might go unnoticed are the priest kissing the altar at the beginning and end of the Mass.
 
What is the meaning of these kisses?  Pope Francis spoke of them in his General Audience on December 20, 2017: “Normally, while the entrance hymn is sung, the priest, with the altar servers, approaches the altar in procession, and salutes it with a bow and, in a sign of veneration, kisses it and, when there is incense, incenses it. Why? Because the altar is Christ: it is the figure of Christ. When we look at the altar, we are looking exactly at Christ. The altar is Christ. These gestures, which could pass unobserved, are highly significant, because they express from the very beginning that the Mass is an encounter of love with Christ, who, by offering his Body on the Cross, became ‘the Priest, the Altar and the Lamb.’ The altar, in fact, as a symbol of Christ, is ‘the center of the thanksgiving that is accomplished through the Eucharist’; and the whole community [gathers] around the altar, which is Christ, not to look at each other, but to look at Christ, because Christ is at the center of the community.”
 
At Mass, our encounter is not only with Christ, but also with the Communion of Saints.  During the early centuries of the Church, the altar was often a stone placed over the tomb of a martyr. In John’s Revelation, he saw an altar in heaven and underneath it the souls of all the martyrs (Rev 6:9). When the altar is consecrated, relics of the saints are placed in it, and when the priest kisses the altar, he is also kissing these relics and invoking the prayers of the saints whose relics are within the altar.
 
And so this encounter of love with Christ, the altar, and with His entire Church, begins and ends loving and reverently with a kiss.