My pastor said that during the Easter season we should say the Regina Coeli prayer instead of the usual Angelus. When did that become the required practice?
I wasn't able to discover when it was decided that the Regina Coeli would replace the Angelus during the Easter Season, but I can say that this has been the practice for a long time. The Catholic Encyclopedia from 1910 mentions it, so the practice is at least that old, and I would say probably much older, since both prayers are from the 12th century.
I think the reason for the change makes sense once you consider the words of each prayer. The Angelus is all about the Annunciation, when the angel Gabriel appeared to Mary and Jesus was conceived by the power of the Holy Spirit.
The Regina Coeli, however, is very much about the resurrection of Jesus, which is what we celebrate during the Easter Season. Here is the Regina Coeli:
V. Queen of heaven, rejoice, alleluia.
R. For he whom you did merit to bear, alleluia,
V. Has risen as he said, alleluia.
R. Pray for us to God, alleluia,
V. Rejoice and be glad, O Virgin Mary, alleluia,
R. For the Lord is truely risen, alleluia.
Let us pray. O God who gave joy to the world through the resurrection of your Son our Lord Jesus Christ, grant, we beseech you, that through the intercession of the Virgin Mary, his mother, we may obtain the joys of everlasting life, through the same Christ our Lord. Amen.
It is also filled with alleluia's, which is the great Easter word of praise. So, the change is very good and fitting.
I am in a debate with someone who thinks that Catholics contradict themselves by saying that Jesus is the foundation of the Church while also believing in the authority of the pope. How should I respond?
This does seem like a contradiction at first. But, Scripture provides the answer.
If there can only be one foundation to the Church, or if the Church is only built on the work of one person, then St. Paul must be entirely confused. After all, in 1 Cor 3:11 he says that the foundation is Christ, but in Eph 2:20 he says that the Church is built on the foundation of the apostles and prophets (with Christ Jesus as the cornerstone). In Rev 21:14, we see that the "New Jerusalem", which is an image of the Church, has twelve foundations, each one representing a different apostle.
So, which one is it? Is the Church built on Christ or is it built on the apostles and prophets? It’s both. The foundation of the Church was first laid back in the Old Testament, with the covenants that God established with man and in the words of the prophets, who spoke of a great gathering of all mankind around the Messiah (cf. Gen 12:2-3; Exo 19:6; Ezek 20:41; Dan 7:14; etc.). When Jesus came, He chose 12 apostles and they worked together to further lay the foundation of the Church and to build upon it.
This is what the pope, as the successor of St. Peter, continues to do today. He works with Jesus -- or, to put it another way, Jesus works through the ministry of the pope -- to ensure the continued stability of the Church. Jesus Himself said that He would build His Church on Peter (cf. Mt 16:18), so it is quite logical that we would consider his successor to be a foundational figure.
He also says that Catholics aren’t Christians because the bible only refers to “Christians”, not to individual denominations.
Well, there is a sense in which he is right. Scripture does not envision the denominationalism that currently exists within Christendom. Christ did not build His Church with the hope that it would one day splinter and divide into thousands of different denominations. He built His Church to be one, holy, catholic, and apostolic.
So, the only way to find His Church among the thousands of competing ecclesial communions is to ask oneself: Which of these has unity, holiness, catholicity, and apostolicity as marks of its very nature? Only one does.
Another way to answer this question is to go back before the splintering began, look at the belief and practice of that Christian community, and see if any church exists today that has maintained continuity of belief and practice with that community. Only one has. It is a historical fact that, before groups began breaking off, to be Christian was to be Catholic.