Think of those early Christian’s standing up, beginning in Jersalem, empowered by the Spirit to speak powerfully the Word of God. We see this unfolding here..
Act 2:36 Therefore let all the house of Israel know assuredly, that God hath made that same Jesus, whom ye have crucified, both Lord and Christ.
Act 2:37 Now when they heard this, they were pricked in their heart, and said unto Peter and to the rest of the apostles, Men and brethren, what shall we do?
Act 2:38 Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.
Act 2:39 For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call.
But read it all.
Btw if you are new to this blog, Acts is a book which repeats every 30 days in my reading cycle. And a while back in my postings I gave a summary of the speeches presented in the book. We used it as a small group study.