What does Acts 17:23 mean?
Paul is speaking to Stoic and Epicurean philosophers in the Areopagus. "Areopagus" means "Ares's hill"; it is the court where myths claimed the war god Ares was tried for killing the son of Poseidon. It's also the hill where Socrates was tried and convicted to death for promoting the worship of foreign gods. The Roman statesman Cicero insisted that even the private worship of a god not endorsed by the Roman Empire is illegal.It is bad form to use flattery to convince one's audience instead of logic. So, brazenly using their own debate style against them, Paul insults these critics, instead. When he arrived in Athens, he noticed the entire city was filled with idols (Acts 17:16). From the Areopagus, the people can see the temple of Hephaestus as well as the Parthenon: the temple of Athena. Paul starts by calling the philosophers "very religious," meaning, superstitious. The Stoics consider themselves to be the epitome of cold logic, and the Epicureans don't believe in the spirit world. They like to think adding an "unknown god" to their pantheon is judicious, not superstitious.
Paul has a purpose in using a blunt approach, however. He's not being brusque just to make others angry; by tying in the Jewish Creator God to the "unknown god," he asserts that he is not teaching a foreign deity. He goes on to identify his God as the Creator who is Lord of heaven and earth. As with all good debaters, he starts from a common point and leads his audience to his conclusion. The philosophers dismiss him when he says this God raised someone from the dead, but they have no reason to charge him with teaching the worship of a foreign god.
The origin of the altar to the unknown god is debated. Diogenes Laërtius wrote of a pestilence that threatened Athens. The people sacrificed to every god they could think of to no avail. When consulted, Epimenides said to let loose a flock of sheep around the Areopagus. Where they lie down, the people were to make an altar to the god they missed—the unknown god. An alternate explanation is that if a monument to a god was so worn it was no longer clear who the monument was for, it was inscribed "to an unknown god."