What warning does Apollo give Phaeton?

Apollo warns Phaeton against wishing to drive the chariot:

"You ask for too dangerous of a gift. Even Zeus, the mighty god of thunder, will not drive the chariot of the Sun. The horses breathe out flames and the chariot itself is fiery hot. So powerful are the steeds that I, a full-grown god, can barely restrain them. What chance would a mortal boy have?"