I was asking about courage and cowardice in general. And I will begin with courage, and once more ask what is that common quality, which is the same in all these cases, and which is called courage?
This quote from Socrates (191e) is relevant for the fact that Socrates is asking for something more than just a description, which partially defines courage. He is asking for a definition of courage that includes all cases in which the word courage could ever be used or conceived. Socrates here seems to be searching for the essence of courage disembodied from any particular context. It is this task of defining courage in isolation at which Nicias and Laches fail. One may also see in Socrates's propensity to search for the meaning of a disembodied abstract form of courage the very beginning of Plato's interest in the disembodied world of "forms" so prominent in his later philosophy.
Because you seem not to be aware that anyone who is close to Socrates and enters into conversation with him is liable to be drawn into an argument, and whatever subject he may start, he will be continually carried round and round by him, until at last he finds that he has to give an account both of his present and past life, and when he is once entangled, Socrates will not let him go until he has completely and thoroughly sifted him.
This quote from Nicias (187e-188a), is relevant because reactions such as these led to the death of Socrates in trial. In all of the dialogues, Socrates is famous for toying with and insulting his audiences in order to relieve them of their pretensions. Socrates's attitude is not pure meanness however. By continually embarrassing his audiences, he brings them closer to wisdom and to the truth that they too have no knowledge.
He dresses himself out in words, while seeking to deprive of the honor of courage those whom all the world acknowledges to be courageous.
This point made by Laches (197c) is an apt criticism of several of Nicias's proposed definitions of courage. Although Nicias does not run into a straight contradiction in the way Laches does, he makes his definition more and more abstract in an effort to defeat the arguments of Socrates and Laches. However, in making his definition overly abstract he has departed from the everyday meaning of courage. He has invented an abstract quality but since it does not apply to many people who are considered courageous, his definition no longer refers to the actual quality of courage and therefore has no practical use.
Socrates, I invite you to teach and confute me as much as ever you like, and also learn of me anything which I know. So high is the opinion which I have entertained of you ever since the day on which you were my companion in danger, and gave proof of your valor such as only the man of merit can give.
This quote by Laches (189b) is important for the connection it draws between words and deeds. He respects the words of Socrates because Socrates has shown innate knowledge of the quality of courage on the battlefield. The reason Laches criticizes men who practice the art of fighting in armor is because, on the battlefield, they behave as cowards and show no skill in fighting. Thus, Laches realizes that although such men may have knowledge of a sort, they have not the useful kind that is actually used in fighting. Laches, Socrates, and Nicias, however, have the sort of knowledge that matters on the battlefield. But they cannot hold on to verbal knowledge of the word courage.