As for points of truth upon which to anchor a bridge, Craig Keener observes that there was “some common ground with Epicureans, such as lack of need for temples, but much more with Stoics.” As it was, these two very different groups decided Paul needed to be brought before the Areopagus, the council of Ares, to be heard. After all, like Luke says in v. 21, “all the Athenians and the foreigners who lived there would spend their time in nothing except telling or hearing something new.” Hearing new ideas was like Netflix for them, and they loved binge-watching. They probably looked forward to what he was going to say, thinking, with a smug superiority, “This should be entertaining, if not interesting.”
Verse 21 also clues us in on the method Paul was going to use to begin bridging with the philosophers. He was going to focus on one of three basic questions common across religions and philosophies—the question of epistemology, the question of knowledge (“how we know and how we know we know”). It was a brilliant move, as anchoring on epistemology put them all on the same track, in order to engage truth, for the epistemological question, “how we know,” is foundational. As Schaffer explains, “Unless our epistemology is right, everything is going to be wrong.” What Paul showed the Areopagus was the facts, pointing to the harmony of creation and history with divine revelation as how we know the truth of the gospel. As a bonus, Paul also touches upon two other major philosophical questions: the question of “Being” (what exists)” – metaphysics; and the question of “man and his dilemma” (morals) – ethics. 
Paul begins his speech in v. 22 with a compliment, of sorts. “Men of Athens, I perceive that in every way you are very religious.” And Paul wasn’t exaggerating, Athens was known as religious city, evidenced by the three-to-one ratio of idols to people.
Yet, in their idols, there was an admittance to something lacking. Verse 23: “I found also an altar with this inscription: ‘To the unknown god.’” These people, who valued knowledge so highly, had an admitted lack when it came to knowledge of a certain god. This was absolutely true—a true truth. So, Paul sent across a line to anchor to that truth with the truth of the gospel.
They had a hunger for something, and they were not sure, exactly, for what it was. As we looked at last week, their idolatry was a cry for Jesus not knowing it was Jesus for whom they cried. But Paul knew. And, he didn’t just say he had an answer. He said he had the true answer, with the answer to how we know it is true. “What therefore you worship as unknown, this I proclaim to you.”
In vv. 24-25, Paul starts with what might be called a creational epistemology—i.e. how we know what we know about the Lord God, as revealed in creation. Creation itself, all of nature, the world and everything in it, is evidence of God’s transcendence and power. Creation itself speaks to the reality of God. Observing creation, and all that is in it, is how we know of the Lord God and his attributes. In Romans 1:19-20, Paul puts it this way,
“For what can be known about God is plain to them, because God has shown it to them. For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made.”
The Lord of heaven and earth, the creator, is the originator of all things, giving man not only life, but everything. Considering his vast majesty and power, what does an all-powerful creator God need with temples or shrines? What does he need that man can give him? In comparison to the creator of the cosmos, man’s misguided worship and even the most beautiful of idols are shown to be nothing but paltry and base.
In vv. 26-27, Paul moves into what might be called historical/relational epistemology—i.e. how we know what we know about the Lord God, as revealed in history and the personal nature of man. Paul began touching on the question of Being in v. 25, as the Lord created man, giving him everything. In history, God initially created one man, a personal, relational being, from whom descended all the nations. As man is personal, the Lord, who created man in his image, is personal, enabling God and man to have a relationship. The Greeks poets, who carried authority in Greek life, even speak to that personal relationship, the true truth to which Paul anchors (in harmony with Gen. 1:27). Paul quotes Aratus, in v. 28, “For we are indeed his offspring.” As offspring, man was created in the image of God, like children are in the image of their parents, with a personal parent/child relationship, including the elements of authority and subordination—hence, his sovereignty over nations.