So Paul is going to preach to them beginning in what he feels will be a common ground. They do not know the God that he is worshipping and so it is almost like this is an altar to the unknown God, the God that he is worshipping. It is not really, but he wants to begin with something that they can relate to.
He is talking here, of course, about God the Creator, but he is employing words that would fit right into the Greek speaking world, something that they were kind of familiar with. And his first ploy is to let them know that this unknown God is so great He could not be contained in a temple. What this has to do with is concerning the nature of the God that Paul is worshipping. Now, you have to understand that it is very likely that all we have here is the essence, the outline of what the apostle Paul said. We do not have the whole message and it is very likely that he filled in here with a great deal of material in order to make more specifically clear exactly what it was that he was getting at, but it gives us the sense.
He is talking here at the beginning of his message about the nature of God. Now, he could compare that very easily to the nature of those idols which were dead. Well, his God is alive! He made everything; He was not created, He is Creator. That is the approach at the beginning.
There cosmos indicates the created physical universe, heaven and earth, everything. Back to the book of John, this time in chapter 13, where Jesus used the word cosmos, or at least John did talking of Jesus.
There the word is translated world, but it is implying the whole universe - everything - all the stars and all the moons and all the planets.
