Growing up in Danville, people were divided into three groups: Jews, Catholics, and Christians. We had no idea that Catholics were Christians. And people like Mormons and Jehovah's Witnesses were thought of as members of a cult. Everything else was in some foreign country.
Today's first reading reminds us that the apostle, and indeed all of the first disciples were Jews. During the earthly life of Jesus the religion we call Christianity never moved outside that mindset. Jesus's brief ministry between his baptism and his ascension was focused on the people of Israel. He would leave the mission "go out and teach all nations" to his Church, guided by the Holy Spirit.
As we see from the infighting in the first reading there were those in the community who didn't understand this. They wanted to keep things exactly as they had been when Jesus was around. I'm sure they were quite fond of Matthew 5:18
For truly, I say to you, till heaven and earth pass away, not an iota, not a dot, will pass from the law until all is accomplished.
It is only after Peter's vision of the great sheet in which all the animals of the world were declared clean that he himself understood the true mission of the Church. The struggle over the Jewish identity of the Church would continue for some time. Only much later would Christians come to see themselves as a separate religion.
If we look beneath the surface we recognize that the struggle was not primarily one of theology, but a deeper question of how one looks at the world. Do you look forward or backward?
There were in the beginning and there will always be those who walk through life looking backward. They believe that the best world has past. Change is usually bad. On the other extreme you have those who run forward. Their attitude is, why do I need to study history? In the Catholic Church, this group seems to be subdivided into those who worship Vatican II and those who worship John Paul II, forgetting that both represent only the latter half of the 20th century.
The challenge of being a true Catholic, a true Christian is that we are pilgrims, we are people with a mission, always looking forward, moving forward, and yet keeping ourselves rooted in the full 2000 year history of our faith. The fullness of the kingdom of God is ahead of us not behind.
One of the reasons I became Catholic was that the more I read the more it seemed to me that the church I was in wanted to jump from Jesus to the Reformation, with no real sense of the millennium and half in between. We weren't even taught the history of the baptist church. It was you, Jesus, and a Bible.
Today we are reminded that the Church has always done both, remain the same and change. We continue to move through time toward eternity, guided by the spirit. We learn from but cannot cling to the past, nor should we impose our will for change. It is enough if we can seek to do God's will in the present.