Acts 18 discusses the Apostle Paul's ministry in Corinth, including his interactions with Aquila and Priscilla, his efforts to persuade Jews and Greeks about Jesus Christ, and the challenges he faced due to Roman laws against new religions. The chapter highlights Paul's dedication to teaching and refuting opposition, as well as the introduction of Apollos, who learns more accurately about Jesus after being corrected by Priscilla and Aquila. The significance of this chapter lies in its depiction of the early Christian community's growth and the importance of clear doctrinal teaching.