The theme is that in both stories they want the power and to kill or take over something or some one. Cronus kills his dad and take control of supreme God then is told that one day his kids will try to take over his king spot.
Zeus's mom hid him from his dad so he would not be eaten with his brothers. Cronus swallowed his kids so the phrocey won't be true and they won't kill him. Zeus mother his hid so his dad would not swallow he with the rest of his