This book, as stated in its opening words, is the second of a two-part work written to Theophilus. The first part is known to us as the book of Luke. The early part of Acts records some of the major missionary activities of the Twelve Apostles under the direction of Peter during the time immediately following the death and resurrection of Jesus Christ. The last half of the book outlines some of the travels and missionary work of Paul. It is evident that the book of Acts is not intended to be a comprehensive history of the early Church but is mainly a recitation of the early missionary efforts and the important opening of missionary activity to peoples other than the Jews. A brief outline of the book is foreshadowed by Jesus’ words in Acts 1:8, “Ye shall be witnesses unto me both in Jerusalem (Acts 1–5), and in all Judea, and in Samaria (Acts 6–9), and unto the uttermost part of the earth (Acts 10–28).”
“In Jerusalem.” After an introduction containing an account of the Ascension (1:10–14) and the calling of Matthias to the Quorum of the Twelve (1:15–26), missionary work in Jerusalem goes forth with the outpouring of the Spirit on the day of Pentecost (2:1–13) and with Peter’s bold declaration of the divinity of Jesus Christ and His literal bodily resurrection from the grave. In consequence of Peter’s preaching on this occasion three thousand persons were added to the Church by baptism (2:37–47).
We are shown how on two critical occasions the Sanhedrin refused to accept the testimony of the Brethren. The first occasion arose out of the arrest of Peter and John for preaching in the temple after healing the lame man (3:1–4:4). The second occasion was in consequence of the large number of converts coming into the Church (Acts 5) and resulted in a formal rejection of the apostolic doctrines (5:17–42).
“In all Judea and in Samaria.” This is recorded in three stages. First we are told of the preaching of Stephen and that his martyrdom caused a dispersion of Church members throughout Judea and Samaria (6:8–8:2). Specific mention is made that one of the seven chosen to help with the affairs of the Church was a proselyte from Antioch. This designation means that he was probably of gentile lineage and was converted to Judaism before he joined the Christian Church. Then is recorded the work of Philip and of Peter and John in preaching the gospel in Samaria (a people who are not Jews, although partly of Israelite origin) (8:4–40) and also the baptism of the Ethiopian eunuch (8:26–40) (probably a non-Israelite by lineage but previously converted to Judaism before being baptized by Philip). All of this shows the gradual outreach of the Church: first to Jews, then to non-Jewish Israelites, and then to non-Israelite persons previously converted to Judaism. Then is given an account of the conversion of Saul of Tarsus and his early preaching, first at Damascus and then in Jerusalem (9:1–31). The coming of Saul into the Church presages the remaining portion of the book of Acts.
“Unto the uttermost part of the earth.” This portion also falls into three phases. The first (9:32–11:26) contains the opening of the door for the worldwide extension of the gospel. This was done by the baptism of Cornelius (10:1–11:18) at Caesarea and also the establishment of the Church in Antioch (11:19–26). Both of these events were among non-Israelite people. Cornelius’ entry into the Church inaugurates a new era because he is the first non-Israelite of whom we have record who entered into the Church without first having been converted to Judaism. The second phase (11:27–15:35) describes the continued activity of the Church at Antioch (consisting primarily of gentile members) and of the work there of Barnabas and Saul. The third phase (15:36–28:31) contains an account of the missionary activity of Paul (Saul), being an account of his travels through Asia Minor and Europe, by which he introduced the gospel of Jesus Christ to Jew and Gentile, and especially to the Gentile.
Although the book of Acts tells us of the preaching of only a few of the original members of the Twelve (namely Peter, James, and John), we conclude that the other Apostles were also actively bearing testimony of Jesus Christ and establishing the Church in whatever lands they could reach. Perhaps they visited in the areas east, north, and south of Palestine. People from such areas are mentioned as having been present on the day of Pentecost (Medes, Elamites, Mesopotamia, Cappadocia, Egypt, and Arabia, Acts 2:9–11), and it is probable that the gospel was first carried into these lands by these people returning from the Feast of Pentecost in Jerusalem and was formally established by the leaders of the Church in the ensuing years.