Euthyphro never expected this development and could not cope with it. The thrust of the remainder of the dialogue is that being pleasing to the gods is not sufficient for an act s being pious. If the gods are pleased, it must be for a reason. Now the reason might be found in the effect that the pious act has on the gods. Perhaps it supplies some need the person has.
Water is pleasing to someone thirsty because it satisfies the thirst.
But the gods want for nothing. There is no instrumental value in the pious acts. If they are to pleased by the pious act, it can only be because of the intrinsic value of the act itself. Plato s ultimate answer to the question of what makes a pious act pious is to say that there is a form, piety itself, by virtue of which a pious act is pious. Another example might be helpful.