In the time of the Reformation it was a known practice of the Catholic priests to deny the people the cup during communion. They would give them the bread but not allow them to drink of the cup. The logic was that these people might accidentally spill a drop and dishonor the blood of Christ. So, people routinely went forward for communion and were disallowed full participation and obedience to Christ, who instituted both bread and cup in remembrance of his sacrifice and in anticipation of his return. In response to the Protestant complaint that this practice violates Jesus’ commands, the Catholic Church addressed it at the Council of Trent. This is an ecumenical council and is infallible (as far as they are concerned). The council decided that it would be official Catholic teaching that laity who eat only the bread and are refused the cup have done enough. They don’t need the cup. A small but important moment demonstrating how false teaching gets enshrined and how Catholics are bound by their magisterium in ways that can keep them from obeying Jesus. Countless Catholics will go to Mass this Sunday and be given only the bread, being denied the cup. Though they do make some exceptions for special feast days. Jesus and the apostles did one thing and the Roman Catholic authority does another.