Socrates believed that defining which of the actions taken by man are good, and which are not, provides man with the definition of piety and impiety. Aristotle also felt that "every action and choice, seem to aim at some good; the good, therefore, has been well defined as that at which all things aim."(Aristotle, 1094a)
Socrates also presents a defense for his actions by asking Euthyphro whether the holy acts that man complete make the gods any better. Euthyphro immediately states no, no, that's not what I mean.
By presenting this defense, Socrates seems to be saying that he is not attempting to blaspheme god, or the gods in any way, instead he is learning what it takes to make himself a better man.
In the end Socrates demonstrates that not even the theologian can provide with certainty what defines piety or impiety. He thereby provides himself a defense against the charge of impiety (not that it helped him all that much).
Idea flow chart
Socrates initially presents Euthyphro as a pious man, a theologian who would persecute his own father for murder. At the same time, Socrates is establishing the fact that he himself is considered a neologian (an individual who believes much differently than most of the other individuals in a particular society). From there Socrates shows that he is most interested in what he can do to become a pious individual. He attempts to ascertain what it is that makes a man pious or impious.
He asks of Euthyphro whether he believes that the gods "fought with one another, and had dire quarrels, battles and the like" to which Euthyphro replies that of course they do. Does that make the gods impious? Of course not, they are gods. Euthyphro then tries to explain that piety is 'that which is dear to the gods' while impiety means it is not dear to them. Socrates does not accept this explanation asking Euthyphro, 'a thing is not seen because it is visible, but conversely, visible because it is seen'. This line of reasoning throws Euthyphro off-track.
Socrates then leads Euthyphro further down the line as he provides him with another definition telling Euthyphro "in like manner holiness or piety is the art of attending to the gods?" After Euthyphro agrees to this statement, Socrates again smashes the thought to the ground by asking Euthyphro whether such attending to the gods makes them better, or man better? Euthyphro tells Socrates that such attention does not improve gods, but that man and god (or the gods) seem to benefit equally for some attentions. Socrates asks, then it (piety) 'is an art which gods and men have of doing business with one another?" When Euthyphro continues by stating that piety or holiness is learning how to please the gods in word and deed, by prayers and sacrifices and that 'such piety is the salvation of families and states'. When Socrates sums it up as 'piety, then, is pleasing to the gods, but not beneficial or dear to them?" Euthyphro agrees though obviously tired of the whole argument.
Some of the key words used throughout this entire discussion are piety, impiety, goodness, holiness, art, learning, improvement and better. By implementing these words in a consistent manner, Socrates is able to display the basic concept of good vs. evil, of right vs. wrong, and the art of learning can be taken to a higher plane than what it was at that time.
At the same time, Socrates line of logic was somewhat confusing and discombobulated when he started talking about if the gods truly loved something or someone, would that make it holy, or is it holy because the gods truly loved it.
This was a much deeper thought-provoking idea than almost any other concept in the writings. Socrates tried to take the concept one step further in discussing fear and reverence, stating that they were wrong when they stated that 'where there is fear, there is also reverence, and that where there is reverence, there is also rear. He expanded that notion by saying that fear is a more extended notion and reverence is a part of fear, which is at the point that it became really difficult to determine whether the argument made sense or not.
Aristotle, Nicomachean Ethics, 1094a. Eastern Orthodox Fr. Life of the World (Crestwood, NY: SVS, 1973), 14.