Acts is a history book. It is the second part of the description of the period that begins with the coming of the Lord Jesus into this world and ends with the imprisonment of Paul in Rome. The first part of this description is found in the Gospel of Luke. Acts occupies a key position in the New Testament. Those who learn to understand it properly, gain insight into special facets of God's Plan of Salvation.
As in the Gospel of Luke, we do not find the name of the writer in Acts either. See the section on 'The Gospel according to Luke' for this.
What is clear is the connection that the account of Acts seeks with the account in the Gospel of Luke. Close Luke 24 with the ascension of the Lord Jesus, Acts 1 begins with that. Luke 24 and Acts 1 can, as it were, be superimposed, giving us one complete history.
Beginning with Acts 16:10, Acts is primarily written in the "we" form, showing that Luke spent most of his time with Paul from then on. The description from then on is reminiscent of a travelogue. In any case, it is believed that the book was completed around AD 63/64.
The purpose of Acts is clearly to give an account of the historical events after the ascension of Christ. During this book a large number of the New Testament epistles were written, which therefore cannot be understood as isolated, but above all must be understood against the background of the history in the book of Acts!
In addition, to the extent that we encounter historiography in the Bible, it is always related in one way or another to the nation of Israel! That applies to the Gospels where history is predominantly written, that applies to Acts and that also applies to the book in which we find history described, which has yet to happen: the book of Revelation.
Some expositors have been surprised that Acts ends so "abruptly." Well, that's because Israel's history ends there (for now). From Acts 28, there are only Gentiles in the position of salvation, and Israel (in fact, these were only the two tribes of Judah and Benjamin, the old two-tribe kingdom) has been returned to the ranks of the nations, where it had been before the covenant in Exodus. 19 was taken out. As far as the prophetic word pertains to the future, it is nothing but historiography of history yet to come to pass. And since historiography is always related to Israel, the prophetic word is also related to Israel; and Revelation is also about Israel!
The prophetic plan pertains to God's visible dealings with Israel and the Gentiles (in that order); the hidden plan pertains to the invisible dealings of God with the body of Christ, which is taken from among the Gentiles, or all men.
Whoever holds these ground rules within God's Word immediately discovers that Acts does not yet say anything about the body of Christ, but is working towards the yet future history of the book of Revelation. You could say: just as Acts connects to the Gospel of Luke, so Revelation connects to Acts.
A. 1:1-3 Introduction.
B. 1:4-2:13 Jerusalem. Mission by the Holy Spirit. Equipment of the Twelve.
C. 2:14-8:1a The ministry of Peter (and others) to the people in Jerusalem and the land of Israel.
D. 8:1b-11:30 The ministry of Peter (and others) in the land of Israel.
E. 12:1-23 Jerusalem. Peter imprisoned. Sojourn in Caesarea and conclusion of his ministry.
B. 12:24-13:3 Antioch. Mission by the Holy Spirit. Equipment of Paul and Barnabas.
C. 13:4-14:28 The ministry of Paul (and others) to the people in the dispersion; apart from Jerusalem and the twelve.
D. 15:1-19:20 Paul's ministry in connection with the twelve.
E. 19:21-28:29 Ephesus and Jerusalem. Paul imprisoned. Sojourn in Rome and conclusion of his ministry.
A. 28:30 and 31 Closing.
The content of Acts is summarized in the prophetic words of the Lord Jesus in chapter 1:8. Here He speaks in the time to come (not: imperative!) "...but ye shall receive power, when the Holy Ghost comes upon you, and ye shall be My witnesses in Jerusalem, and in all Judea and Samaria, and to the utmost of the earth". The Savior responds with these words to the question of whether the kingdom would be set up at that time (v. 6). Indeed, we see that the testimony was carried in those three phases:
Jerusalem chapter 1-7
Judea and Samaria chapter 8-12
uttermost part of the earth chapter 13-28
Moreover, Acts 1:11 indicates what the hope was at that time, namely: the (visible) return of the Lord Jesus on the Olive mountain. That is also the future expectation of which the letters from the Acts period speak (see for example 1 Cor. 1:7 and 2 Thess. 1:7).
And so it appears that if - speaking to man - the hidden plan of God had not begun, Acts seamlessly precedes the book of Revelation in which Christ's revelation is central.
In addition, the outpouring of the Holy Spirit in Acts 2 is nothing but the beginning of the new covenant between God and His people.
"Lord, wilt thou at this time restore the kingdom to Israel?" (chapter 1:6, King James Version).