The disciples have been on a mission that probably took a lot out of them. So Jesus takes them away where they could be by themselves (Luke 9:10-17.) But the crowds found out where they went and followed them. Even though Jesus had wanted to be alone with his disciples, Luke says, "He made them welcome."
St. Paul scolds the Corinthians for not making the poor and the slaves welcome to the common meal that preceded the celebration of the Lord's Supper (11:17-24.) They fail to recognize that they are all united in the Body of Christ.
Welcome is the hallmark of an authentic celebration of Mass.