Q: At what point during Mass is it too late for someone to arrive and have it “count”? Some people come a few minutes late and others very late. I think this is wrong.
A: The Baltimore Catechism used to identify the principal parts of the Mass as the Offertory, the Consecration and Communion. If a person was not present for all three parts, he or she was considered as not attending a complete Mass. Because the Church now speaks of the Mass as the Liturgy of the Word and the Liturgy of the Eucharist, I think a person should be present from the Scripture readings through the final blessing of the Mass. Emergencies can make a person late for Mass—but not regularly.
Just as people should not take a stingy approach to human relationships such as marriage or friendship (what’s the least that I can do and still maintain this?), neither should they take a similar approach to the Eucharist, which is a tremendous gift from God and which sends us out to live the faith that we profess there.