“Myth of Er” [Republic]
To understand a bit of Greek thought and bring things together a bit, read the “Myth of Er” which concludes the Republic…
Begin here: “The point is that the gods never neglect anyone who is prepared to devote himself to becoming moral and, by practicing virtue [arête], to assimilate himself to God [theos] as much as is humanly possible” (613b).
The myth begins at 613a and finishes at the “Plain of Oblivion” [Lethe], where each takes a drink, in varying amounts, from the “River of Oblivion” before being reborn into his/her next life [at 621d].
Note how, despite the role of Necessity, one has a certain amount of choice, “No deity [daimon] will be assigned to you: you will pick your own deities. […] goodness makes its own rules: each of you will be good to the extent that you value it. Responsibility lies with the chooser, not with God [617e].”