The apostles’ message throughout Acts is not the plan of salvation. It’s not a theology or a set of doctrines either. It is a person—Christ:
. . . and that He may send Jesus Christ, who was preached to you
before. (Acts 3:20)
Then Philip went down to the city of Samaria and preached Christ unto them. (Acts 8:5)
Immediately he preached the Christ in the synagogues, that He is the Son of God. (Acts 9:20; 17:3)