It is clear that Acts has the same author as the Gospel of Luke. But when was the work written? Current estimates are apt to run between 80 and 90 A.D. The reasons: It is clear that Acts follows on the Gospel, which so many think, without valid reason, belongs to that decade. Second, it is commonly thought that Luke did not know Paul.

The chief reasons are the following:

1. It is said that Acts 15:1-35 clashes with Gal 2:1-10. In Galatians Paul tells of the meeting with the Apostles, and says he compared notes with them and they "added nothing to me." But in Acts 15:29 the letter of the Council tells gentile converts to "abstain from what has been sacrificed to idols and from blood and from what is strangled and from unchastity."
   
   Now of the four items from the letter, one repeats the basic commandment against loose sex. Paul of course speaks against loose sex too. The other three items are taken from the old law, and are just a sop, a concession to the feelings of Jews. But Paul in Galatians refers to basic doctrine. The 3 items in Acts 15:29 are not basic doctrine at all, they are, as we said, a sop to the feelings of the Jews. Paul did preach the three points where they applied, as we see from Acts 16:4. Further, the letter of the Council was addressed only to gentiles in Syria and Cilicia - that did not include Galatia. If the Vatican today sends a letter to the bishops of one region, it does not affect bishops of a different region.
   
   
2. It is said that Acts does not mention Paul's Epistles. True, but the purpose of Acts was to show how the Church finally reached Rome, the center of the world. Acts does show Paul presenting the most basic doctrines of the Epistles, namely, justification by faith, the divinity and resurrection of Christ, and baptism and repentance. In Acts 15:9 Peter says that God "cleansed their hearts by faith." In 16:30 the jailer at Philippi asks Paul what to do and Paul replies: "Believe in the Lord Jesus and you shall be saved". [Here as often saved, means entry into the Church]. At Miletus in Acts 20:21 Paul says he has been "testifying to both Jews and Greeks of repentance to God and of faith in our Lord Jesus Christ. In Acts 13:39 at Antioch in Pisidia Paul says, speaking in a synagogue: "Everyone who believes in Him is made just." In Acts 17:3 Paul explains and proves, "that it was necessary for the Christ to suffer and rise from the dead" and so to atone for sins.
   
   In Acts Paul also does preach that Jesus is the Son of God: Acts 9:20 shows Paul preaching this right after his conversion. A Greek concordance under the word Kyrios, Lord, shows numerous other times Paul called Him Lord, the title Paul also uses for Jesus in his Epistles.
   
   In both Acts and the Epistles Paul does speaks of the need of baptism: cf. 1 Cor 1:14-17; Romans 6:3-8; Eph 4:5; Col 2:12)
   
   
3. It is said that only in Acts does Paul preach the need of repentance. But Paul does preach repentance elsewhere, e.g., Romans 2:4; 2 Cor 7:9-10; 1 Cor 5:3-5. The objection is like the foolish idea that Jesus Himself did not require repentance for forgiveness.
   
   
4. In Acts 21:20-26 at the suggestion of James, Paul goes through the Nazarite ceremony in Jerusalem. Some say this was hypocrisy. But it was not, Paul was just following his own principle of 1 Cor 9:20-22 in which he expresses his standing policy of being all things to all men: "To the Jews I became as a Jew, in order to win Jews; to those under the law, I became as one under the law." There was nothing wrong in the rite itself. It would have been wrong if Paul meant thereby to earn salvation. 5)In 2 Cor 11:23- 29 Paul speaks at length of his sufferings in preaching Christ. In Acts he is pictured going through the sufferings mentioned in 2 Corinthians: persecutions from Jews: 14:2 17:1-10; stoning at Lystra (14:19); scourging at Philippi: 16:22-23.