All of chapter 10, but especially verses 15, 34-35, and 44-48.
15: And a voice spoke to him again the second time, "What God has cleaned you must not call common."
34-35: Then Peter opened his mouth and said: "In truth I perceive that God shows no partiality. But in every nation whoever fears Him and works righteousness is accepted by Him."
44-48: While Peter was still speaking these words, the Holy Spirit fell upon all those who heard the word. And those of the circumcision who believed were astonished, as many as came with Peter, because the gift of the Holy Spirit had been poured out on the Gentiles also. For they heard them speak with tongues and magnify God. Then Peter answered, "Can anyone forbid water, that these should not be baptized who have received the Holy Spirit just as we have?" And he commanded them to be baptized in the name of the Lord. Then they asked him to stay a few days.
Last week, my pastor preached on this text. Then i read it in my personal devotions. Next week, we're covering it in Bible study. That's how it goes sometimes.
The early Church had a problem: were they another sect of Judaism, or were they a new religion? Jesus was Jewish, and He was the Messiah they'd been waiting for. So maybe they were still Jews, but they had just recognized a truth that no one else had seen yet? This meant that a Gentile could convert here and there, but they would have to be circumcised and stop eating bacon-wrapped shrimp and observe their holy days and ritual washings. But then the Jews said, "No, you guys are not one of us. The Messiah hasn't come yet. If you want to worship Jesus, you're worshiping another god and we want nothing to do with you."
So do new converts have to be circumcised? Do they have to observe Passover? Do they have to observe the Sabbath?
Much of Acts deals with these questions -- the book is half Three Stooges/James Bond miracles and prison escapes, and half church meeting reports -- so we'll spend a lot of time talking and thinking about this stuff. What does it mean to be Christian? What are the rules? What do you have to do to be saved? And, having been saved, what do you have to do to stay that way?