Question

jason was the son of the lawful king of iolcus, but his uncle pelias had usurped the throne. pelias lived in constant fear of losing what he had taken so unjustly. he kept jasons father a prisoner and would certainly have murdered jason at birth, but jasons mother deceived pelias spies. meanwhile, the infant was bundled off to the wilderness cave of chiron the centaur, tutor of heroes. jason was tutored in the lore of plants, the hunt and the civilized arts. when he had come of age, jason set out like a proper hero to claim his rightful throne. 5. why doesnt pelias kill jason when he is born?

Explanation:

Jason was the rightful heir to the throne. Pelias, his uncle, was afraid of losing his power. So he sent Jason away as an infant. If Jason hadn't been born, Pelias wouldn't have had this fear and thus wouldn't have needed to take such actions to secure his position.

Answer:

Because Jason was the rightful heir and a threat to Pelias's power.