In Greek mythology Cronus ate his children. After he dies Zeus eats Metis, while she is pregnant with Athena. What is it with gods eating their children?
I remember reading a reference of a tale (I think it was on Joseph Campbell's Hero of Thousand Faces, but I have to search for this passage and than provide a proper quotation and reference here) in which a man sees a pregnant woman who walks next to the river shore. Then, she gives birth to a child and after that, here face transforms on that of a hideous monster, devours that child she just gave birth to an leaves.
Many deities are both givers of life and bringers of destruction. You (as a creation-child of this divinity) are given a life, but are irremediable condemned to die too. Time, embodied by Chronos will give you origin, but then you'll age, and Time will eventually take your life. This duality bringer of life/destruction applies to many divine entities (there is no Life without Death) and highlights the cyclic nature of life/time in many different cultures.
So, the significance of eating its own children is that the creator divinity gives its creations a life which will have an end. There is a cyclic nature for birth, death and (re)birth and the divinity does not consider the death of the creations-children as something evil (even if its eating them). It is part of the cycle.
Cronus tried to eat Zeus but was tricked into barfing him back up along with his brothers and sisters. Cronus did this because he wanted to stay king and thought that if he ate all the possible airs, he would stay king forever. Unfortunately for him, when Zeus was barfed back up, he waged war on Cronus for his throne for 10 years. When Zeus finally became king, he married his first of many wives, Intelligence (Metis). Metis was said to have 2 kids, one girls and one boy. The boy was said to be powerful enough to overthrow Zeus one day, so under the instructions of Earth (Gaia), he tricked Metis into turning into a fly and ate her while she was pregnant with their first child. Athena was later birthed from Zeus skull but Zeus made sure that no one else could overthrow him for Metis was the only spouse capable of giving birth to such a powerful son. Long story short they eat their kids so that they can stay in power for as long as possible.
It possible there is an underlying lesson, similar to Abraham taking Isaac to be sacrificed, then God telling him not to do it now or at any point in the future. (Presumably, before Abraham, sacrificing one's own children was socially acceptable behavior.)
We need to break out Kronos and Zeus/Metis.
In the case of Kronos, he eats his own children, and is overthrown. Likely part of the function of this story is to show the barbarity of the old gods, who are distinctly chthonic. (Note the discussion of ritual sacrifice in the link, which also mention burning as opposed to consuming the sacrifice. But Zagreus was torn apart and eaten raw by titans, a practice know as sparagmos.)
You see Kronos mirrored in infamous humans, chiefly Tantalus, who dismembered and cooked Pelops to serve to the Olympians for dinner. Tantalus received one of the most famous punishments in the underworld, and the practice seems to have become a family tradition--his grandson Atreus did the same to his brother, feeding him Thyestes his own child. Atreus himself came to a bad end, killed by the incestuous progeny of his brother. Atreus's son, Agamemnon, a baby killer who sacrificed his own daughter, also came to a bad end, murdered in the bathtub by his wife.
(Dante, in his Inferno, has a special place in hell where Ungolino is forced to eat their own children;)
- Killing your own children is bad. Eating them is worse.
ZEUS & METIS
Zeus, known for his scheming, figures out a way around this with Metis.
- Zeus doesn't directly consume his child, but instead consumes a surrogate--the pregnant mother.
In this case, it turns out well, with Athena, Goddess of Wisdom, springing fully armored from his head!
HOW KRONOS & ZEUS' STORIES RELATE
The unifying idea in both cases is that the new generation supplants the old. In both cases, the deities are reacting to a prophecy the would be overthrown by their offspring.
This is analogous to aging and loss of capability in the natural world. You see it in wolf and lion populations where younger, stronger males take control from older, declining pack or pride leaders.
James Frazer extrapolated this into an entire mythology of king killing in the Golden Bough. Zeus uses a Frazer-like trick to avoid the sin of killing/eating of his own offspring.
They all did it because prophecies told them their child will overthrow them. Cronus overthrew his father and ate all of his children (except Zeus) to stop it. Zeus didn't actually eat his children, but he was told by the prophecy his second child with Metis will overthrow him, so he ate Metis to stop it before it happens. While he succeeded, she was already pregnant and Zeus ended up giving birth to their first (and only) child Athena.