Awaiting trial, Socrates meets Euthypro who is on his way into court to prosecute his own father for murder. Euthypro explains that while his family and mother think it impious for him to indict his father, they do not have a clear understanding of piety. Euthypro explains that his actions are just and in favor with the gods, because murder is wrong; even if it was unintentional.
Socrates tells Euthyrpo that he is right, and asks that Euthypro might become his teacher, so that he may be educated on what exactly piety is, and how he may accurately discriminate between which actions are loved by the gods and which are punishable.
In this exchange with Euthypro, Socrates (or Plato) easily extracts the inflated view that Euthypro holds of his understanding of morality and the importance of 'acting piously'. Euthypro explains that piety is correct knowledge of hot to sacrifice and petition to the gods, and that by carrying our these tasks in correct format, the gods are pleased. Socrates claims to have no knowledge of these things and asks Euthypro to further explain how we may please the gods.
Like a psychiatrist who remains a step ahead of his patient, waiting patiently to bring their client out of some mental delusion, or false belief, by coaxing them with a series of questions; Socrates plays dumb and gets Euthypro to counter his own theory that a thing is pious because it is something that the gods undoubtedly love. While the patient answers the questions of his therapist, he unwittingly brings a truth to the surface--perhaps one that he has hidden from himself.
This is an important viewpoint to examine, because it is one held by many. Loads of people, in my experience, are convinced that they have pinpointed which actions are acceptable, or in accordance to what God wants. In the same vein, they are just as certain that they have great knowledge of actions that are punishable and even hated by God. It is these convictions (assumptions rather), that can lead us to great prejudices. And it is these same convictions that can deter us from examining the origins of the moral rules which we let govern our very lives.
We should care more about what actions are just and fair when dealing with our fellow man, than what actions are in exact accordance with ancient temple laws. After all the gods love what is pious because it is pious; it is not pious because the gods love it.