If all the bishops are called to participate in a council and actually represent the entire Catholic Church, the assembly is called ecumenical, which means universal. During the past two thousand years the Catholic Church has had 21 Ecumenical Councils.
Authority
St. John Paul II ’s Unitatis Redintegratio, § 4, states: “The term ‘ecumenical movement’ indicates the initiatives and activities planned and undertaken, according to the various needs of the Church and as opportunities offer, to promote Christian unity.”
But here we focus on ecumenical as the universal Church speaking with one voice to the whole world.
“Now there were dwelling in Jerusalem Jews, devout men from every nation under heaven. And at this sound the multitude came together, and they were bewildered, because each one heard them speaking in his own language. And they were amazed and wondered, saying, ‘Are not all these who are speaking Galileans? And how is it that we hear, each of us in his own native language?’” Acts 2:5–8.
Rabbi Yeshua‘s most vivid sign of true teaching occurs when a pope, the Vicar of Christ, teaches in union with all the bishops of the world (except those unable to come for reasons of health, diocesan needs, government travel restrictions, or some other grave reason).
During His mortal life, when Rabbi Yeshua wanted to get our attention for something really important, He would begin, “Amen, Amen, I say to you.” Now He gets our attention through Ecumenical Councils, which have been recognized as acts of the Holy Spirit since Peter had declared at the Council of Jerusalem, “… it has seemed good to the Holy Spirit and to us …” Acts 15:28.
Each pope, of course, as Vicar of Christ, has supreme authority over the Church. He does not need the approval of a Council to issue decrees. However, in practice, a pope will call a General Council to show that a particular teaching is accepted by the whole Church. Too, a pope deciding a grave matter of prudent judgment may wish to gather advice and counsel from the attending bishops.
The Pope and All the Bishops
An Ecumenical Council, also called a General Council, is a solemn congregation of the Vicar of Christ together with the world’s Catholic bishops to address with him issues before the Church. During the two thousand years of Church history there have been 21 Ecumenical Councils. Each articulated some important truth that Rabbi Yeshua wished us to have. “[The Holy Spirit] will … take what is mine and declare it to you” Jn 16:14.
Vatican II 1962-1965 reaffirmed the principles of Catholic faith and morality, and authorized many developments in the Eucharistic Liturgy, including the Missal of Pope Paul VI, the Ordinary Form of the Holy Sacrifice of the Mass. It also authorized changes in the Church’s administrative structure.