Holy Spirit has stirred Paul’s heart to speak up about the idol worship in Athens, the worship of idols being abhorrent to worshipers of the One True God. So waiting for Silas and Timothy to catch up to him (Luke, having gone elsewhere until Acts 20:5-6) Paul verbally tackles this rampant idol worship in Athens. That they worship idols has caught him unaware.
With the stirring of the Holy Spirit and his zeal for God’s Truth he makes presentation for Christ and defends faith confidently daily in synagogue, as is his custom.
Three Jewish sabbaths, not excluding the days in between, Paul argues against idols. The philosophers debate with him, some call him a ‘babbler’, and some accuse him of proclaiming foreign divinities. He straightforwardly witnesses to the Good News of Jesus’ Resurrection and is defender of God, Christ, and the Holy Spirit during debates.
During these debates in which the philosophers gather, then among themselves try unsuccessfully to philosophically reason meaning of Paul’s new teachings according to their patterns. They’re curious and he is eloquently faith filled. So they ask him to come and speak at the Areopagus.
Athens is the seminary for philosophers. The Areopagus, or Mars Hill (dedicated to the heathen god of war) is the place where Athenians hold their Supreme Court of judicature.
But Paul is not asked to speak at the Areopagus as a criminal. They request him to come speak out of their distemper. In the past the new things these men discovered became quickly cheap, and they wanted the newer still. They are on a quest for the newest thinking. In the Areopagus Paul will witness that God is ready to be found.