The overall theme of the book of Acts in the Bible is the growth of the early church. And the key verse is “you will receive power when the Holy Spirit comes on you; and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the ends of the earth” (1:8NIV). That’s the mission of the church. Believers are to be God’s witnesses.
The book of Acts in the Bible describes the first 30 years of the church. It’s an historical narrative that was written by Luke who was a companion of Paul (Col. 4:10-14; 2 Tim. 4:11; Phile. 24). He wrote it to educate Christians about the early church.
The main point of Acts is that God’s witnesses spread the gospel message and established churches.
A time line of major events in Acts (concentrating on Acts 1-12) is given below. And it is followed by a summary of the book (also concentrating on Acts 1-12).