Oracles are the way the people in the mythological world found out what was going to happen in their future. It was their way of foreshadowing events. All the oracles come true. Oracles can be compared to prophecies in the Bible. For example, Cronus got the oracle that said his children would try to betray him and one would succeed so Cronus decided to swallow all his children. Zeus ended up tricking Cronus and making him swallow the stone instead. So the oracle ended up being true.
Would the gods have acted differently if they didn’t have any knowledge of the future?