If you are interested in philosophy, the New Testament, and Koine Greek, then you need to try to read some of Epictetus. Epictetus was a Stoic philosopher of the 1st-2nd centuries. Epictetus' works are in literary Koine, the same Greek as the New Testament. He uses many phrases and wordings that occur throughout the NT. You can find some more about him at http://www.letsreadgreek.com/epictetus
(my site). If you go to the Reading Schedule on those pages you will find some helps for reading his Enchiridion.