When you go to visit someone, it’s very, very rare to sit down immediately to the “main course” being served for dinner. It takes a while for hosts and guests to greet each other, get comfortable, attend to any special details of the gathering, and so forth. As a matter of fact, just “getting together” is a significant event for human beings – being “social animals” like we are! – and so we enjoy just doing that. It’s not insignificant.
You can see the same sort of dynamic going on at Mass. Our Eucharistic assembly takes a little time at the beginning of Mass first to greet God and each other and then to grow comfortable in each other’s presence. It’s not insignificant!
The dialogue begins with a greeting between priest and congregation: a formal wish “The grace of our Lord Jesus Christ, etc., be with you” is answered “And with your spirit.” The priest is not the host at the gathering – God is! – but the priest is a divine representative in leading the assembly. He connects us with God. It’s easy to overlook the importance of this little ritual, which not only helps put us in the right frame of mind but also represents the basic thing we’re trying to accomplish: to get connected with the Lord.