A dilemma as to whether things that are morallygood are commanded by God because they are morally good, or whether they are morally good because they are God's commands.
Wiktionary
Origin of Euthyphro Dilemma
Found in Plato 's dialogue Euthyphro, in which Socrates asks Euthyphro, "Is the pious (τὸ ὅσιον) loved by the gods because it is pious, or is it pious because it is loved by the gods?"