I am debtor both to the Greeks, and to the Barbarians; both to the wise, and to the unwise.

But Paul, in his preaching of the Gospel, is a debtor to deliver the word not to Barbarians only, but also to Greeks, and not only to the unwise, who would easily agree with him, but also to the wise.

Before you take your debtor to court,first open his book of remembrance to see how much he has patronized you over the past years.

And there were certain Greeks among them that came up to worship at the feast: / The same came therefore to Philip, which was of Bethsaida of Galilee, and desired him, saying, Sir, we would see Jesus.

And some of them believed, and consorted with Paul and Silas; and of the devout Greeks a great multitude, and of the chief women not a few.

Barbarian Horde
This will be lot and lots of wild-screaming people advancing under a cloud of dust in order to devestate more civilized parts. They are a bit like locusts, except that they kill people direcly.