Medea has just killed four people which are Creon the king of Corinth, the princess whom Jason is in love with, and her two little children. Jason then prays to gods, especially Zeus, father of all gods, to punish Medea for her crimes. From the context of the quote, the chorus is addressing the audience about the unexpected and unbelievable end of the play. Medea then gets away to Athens with a chariot lent to her by Helios, the sun god and her grandfather.
Euripides always uses this kind of conclusion to end most of his works. Euripides suggests that the general theme of the quote is gods are not like what we think they are supposed to be. In other words, we can not expect much from the gods. Instead, we have to handle our matters on our own. The phrase, "Many are the Fates which Zeus in Olympus dispenses," tells us that gods do not favor mortal people. Even if gods do help mortals, that's only because those mortals have some kind of relationship with the gods. So, Euripides tells this story not in favor of the gods.
The general thems is gods are not as good as they are supposed to be.
Medea has been exiled for three times: from her home country near the Black Sea, from Jason's homeland Iolchos, and now from the city of Corinth. We would naturally think that a woman like Medea, being exiled for many times, is the most vulnerable and most powerless woman. She has got no friend and no citizenship. At the time of Euripides, being an exile is not an interesting position that a person wants to be in. It is like a suicide. Most people at that time in Greece view strangers as barbarians with no intelligence at all. In addition, Medea is going to be an exile with two children. She is supposed to be in lots of trouble. On the other hand, Jason has won the princess of Corinth's love. He is going to be Creon's son-in-law. Jason abandon's Medea after all she has done for him. Jason doesn't fear Medea at all because he has support from Creon, king of...