The surprising thing about that first reading is that after Peter and the others talked to the Pentecost crowd in Jerusalem they went on to baptizing three thousand people.
It leads to all kinds of questions. Like, where did they do it? What words did Peter and the others use?
How could they have done it so quickly when later on the Apostles set up a three year training program for converts? It takes me back to 1941 when the U. S. Army began a three-month training program for new officers. The cadets who had labored through four years at West Point complained bitterly about the ninety-day-wonders.
Another question that arises is: what happened afterwards to those three thousand people baptized that day? Well, I guess there is an answer in later chapters in The Acts of the Apostles. They describe the way they set up a community life for everyone.
Another question is: in becoming Christians did they give up their Jewish Religion? The answer is No. Their Jewishness didn’t seem to be a contradiction to them. The only thing that became different was that they bent kosher rules by eating along side Gentile Christians who enjoyed bacon.
Almost fifty years would pass before the Pharisees would begin insisting that Jewish Christians could not have it both ways. The Pharisees told them they would have to stop eating with Gentiles if they wanted to be recognized as Jews. Matthew wrote his Gospel as a denial of that stand the Pharisees were making.