As Ralph thinks about the ocean as a barrier, what does Simon say to him that interrupts his thoughts in William Golding's Lord of the Flies?

By chapter seven of William Golding's Lord of the
Flies, Ralph is getting discouraged and afraid that none of them will ever be rescued.
In the passage to which you refer, Ralph is reflecting on what has happened to them. He has been
biting his nails to the quick without realizing it, and all of them are

dirty, not with the
spectacular dirt of boys who have fallen into mud or been brought down hard on a rainy day. Not
one of them was an obvious subject for a shower, and yet—hair, much too long, tangled here and
there, knotted round a dead leaf or a twig; faces cleaned fairly well by the process of eating
and sweating but marked in the less accessible angles with a kind of shadow; clothes, worn away,
stiff like his own with sweat, put on, not for decorum or comfort but out of custom; the skin of
the body, scurfy with brine—

Ralph is
dejected and feels quite hopeless about their future. He walks down to the rocks on the beach and
looks down at his feet, watching the incoming waves. This seems to soothe him for a time, but
then he looks up. He saw the vastness of the ocean and "the almost infinite size of this water
forced itself on his attention." In a moment he is confronted with the stifling realization that
his life will end on this island. "[H]ere, faced by the brute obtuseness of the ocean, the miles
of division, one was clamped down, one was helpless, one was
condemned,"

Simon interrupts these thoughts to say, quietly into
Ralph's ear, “You’ll get back to where you came from.” We have always felt as if Simon knows
things that no one else knows, but this is the most startling thing he has said thus far--and
both Ralph and the readers believe him. This gives Ralph hope that he and the others will be
rescued, which they are. Simon was right.