Best way to answer that is to read Augustine.
But, here goes nothing: Your quote only explicitly mentions omnipotence, but it implies things about omniscience. Let's talk about just niscience (knowing something) not knowing everything. Sometimes, knowing more means you learn a limitation - like when 19th century physicists thought they knew practically everything in physics, but 20th century physicists learned there are limits on knowing an electron's position and momentum at the same time, or Godel proved that more powerful mathematical systems have more things in them that are both true and not provable at the same time. If you claim God knows everything, do you mean He knows all the limitations on what can be known at once? the Epicurius quote assumes the answer to that questions is both yes and no, and then says any answer you give causes a paradox, but Epicurius has already caused the paradox, and is blaming the people he questioned instead of facing up to that. So he's being intellectually dishonest.